Model I used: 
<NOVA FURRY XL - IL V15.5> 


          
Prompts: masterpiece, best quality, amazing quality, very aesthetic, high resolution, ultra-detailed, newest, scenery, simple background, trio, 3boys, portrait, from front, full body view, (little anthro fox:1.1), (male:1.6), orange fur, young, very short, (short black hair:1.6), (fluffy thick hair:1.3), detailed black eyebrows, bushy orange tail, tail with white tip, ears brown, green eyes, (checkered onesie red and black), brown hands, (five fingers:1.3), paw with five fingers, black claws, open smile, (detailed canine teeth:1.3),

BREAK,
masterpiece, best quality, amazing quality, very aesthetic, high resolution, ultra-detailed, newest, photorealistic, masterpiece, best quality, amazing quality, very aesthetic, 4k, high resolution, ultra-detailed, absurdres, newest, scenery, intricately detailed, masterpiece, best quality, amazing quality, very aesthetic, newest,
---
BREAK,
trio, furry, full body view, (male, young), furry, anthro, little anthro pomsky, (male:1.6), (Grey and white fur:1.6), (short black hair:1.6), (fluffy thick hair:1.3), (dark gray ears:1.1), (detailed canine teeth:1.3), dark grey paws, detailed fangs, black claws, detailed thin black eyebrows, Heterochromia, blue and green eyes, smiling, looking at viewer, 3boys, abs, pink hair, fingerless gloves, toned, toned cub, looking at viewer,
---
BREAK,
"anthro, (furry:1.4), trio, 3boys, (male:1.6),
BREAK,
(young, young child, very young, kid, cub age, 9 years old), anthro, small body proportions, (short:1.6), (shortstack:1.2), little furry wolf, (grey fur:1.3), (wolf ears:1.1), grey and white tail, (aqua hair:1.2), short hair, (thin aqua brows:0.8), purple eyes, black claws, detailed fur, white countershading, white inner arms, (5 fingers:1.2), (black pawpads:0.8), 4 toes, white toes, black track suite
BREAK,
<lora:StS_Age_Slider_Illustrious_v1:-3>
<lora:StS-Illustrious-Detail-Slider-v1.0:4.5>,
masterpiece, best quality, amazing quality, very aesthetic, high resolution, absurdres, depth of field, newest, ultra-detailed, detailed eyes, detailed fluffy fur, dynamic lighting, 8k, HDR, ultra-HD, highly detailed, HDR, realism, realistic, realistic lighting, caustic shadows, (volumetric lighting:1.3), (cinematic lighting:1.3), complimentary lighting, (view from front:1.5),
BREAK,
Negative prompt: worst quality, lowres, low quality, bad quality, bad male anatomy, (female, girl:1.9), bad female anatomy, bad explicit, poorly drawn face, bad face, bad facial expression, ugly, bad hands, morbid, deformed, disfigured, mutilated, malformed, missing body part, malformed hands, bad feet, fused legs, broken legs, bad body proportions, gross proportions, disappearing hands, fused hands, fused body part, fused legs, (fused digits, missing digit, extra digit), bad artist, bad background, cropped, watermark, username, signature, not in perspective, error, jpeg artifacts, squares, blurry image, not in perspective, plain pose, plain figure, old, oldest,, (human ears, human), claws, long hair, girl hair, pony hair, visible penis, blush on snout, green hair, muscular, bodybuilder, muscles, (old:1.9), (adult:1.9), (teen:1.9), tattoo, human hands, (monochrome:1.5), (worst quality, low quality:2), lowres, bad anatomy, bad hands, text, error, missing fingers, extra digit, fewer digits, cropped, worst quality, low quality, normal quality, jpeg artifacts, (signature:1.5), watermark, username, blurry, speech bubble, text, monochrome, censored, nose, snout, (red eyes:1.9), background, logos, long torso, shoes, orange hair,
Steps: 36, Sampler: Euler a, Schedule type: Automatic, CFG scale: 5.5, Seed: 3783096032, Size: 2048x2048, Model hash: c4da45e49d, Model: novaFurryXL_ilV155, Denoising strength: 0.6, Lora hashes: "StS_Age_Slider_Illustrious_v1: bb11fa34470b, StS-Illustrious-Detail-Slider-v1.0: 2e7a68ec7e2e", Version: f2.0.1v1.10.1-previous-669-gdfdcbab6

+[UPSCALING]

Detail Inpaint - Eyes

blue eye, eyesHD, <lora:Eyes_High_Definition:1.7>
Steps: 45, Sampler: Euler a, Schedule type: Automatic, CFG scale: 5.5, Seed: 650577025, Size: 2048x2048, Model hash: c4da45e49d, Model: novaFurryXL_ilV155, Denoising strength: 0.5, Mask blur: 20, Inpaint area: Only masked, Masked area padding: 100, Masked content: fill, Lora hashes: "Eyes_High_Definition

green eyes, eyesHD, <lora:Eyes_High_Definition:1.7>
Steps: 45, Sampler: Euler a, Schedule type: Automatic, CFG scale: 5.5, Seed: 650577025, Size: 2048x2048, Model hash: c4da45e49d, Model: novaFurryXL_ilV155, Denoising strength: 0.5, Mask blur: 20, Inpaint area: Only masked, Masked area padding: 100, Masked content: fill, Lora hashes: "Eyes_High_Definition

purple eye, eyesHD, <lora:Eyes_High_Definition:1.7>
Steps: 45, Sampler: Euler a, Schedule type: Automatic, CFG scale: 5.5, Seed: 650577025, Size: 2048x2048, Model hash: c4da45e49d, Model: novaFurryXL_ilV155, Denoising strength: 0.5, Mask blur: 20, Inpaint area: Only masked, Masked area padding: 100, Masked content: fill, Lora hashes: "Eyes_High_Definition

Steps: 50, Sampler: Euler a, Schedule type: Automatic, CFG scale: 5.5, Seed: 734911356, Size: 2048x2048, Model hash: c4da45e49d, Model: novaFurryXL_ilV155, Denoising strength: 0.36, Mask blur: 4, Inpaint area: Only masked, Masked area padding: 112, Version: f2.0.1v1.10.1-previous-669-gdfdcbab6


Detail Inpaint - Pajamas

dark blue star pajamas,
Steps: 70, Sampler: Euler a, Schedule type: Automatic, CFG scale: 5.5, Seed: 3780722693, Size: 2048x2048, Model hash: c4da45e49d, Model: novaFurryXL_ilV155, Denoising strength: 0.5, Mask blur: 20, Inpaint area: Only masked, Masked area padding: 160, Masked content: fill, 


Detail Inpaint - Teeth

(detailed canine teeth:1.3)
Steps: 46, Sampler: Euler a, Schedule type: Automatic, CFG scale: 5.5, Seed: 2890016068, Size: 2048x2048, Model hash: c4da45e49d, Model: novaFurryXL_ilV155, Denoising strength: 0.38, Mask blur: 4, Inpaint area: Only masked, Masked area padding: 120, Version: f2.0.1v1.10.1-previous-669-gdfdcbab6

Detail Inpaint - Paws

brown hands, (five fingers:1.3), paw with five fingers, (black pawpads:0.8),
Steps: 46, Sampler: Euler a, Schedule type: Automatic, CFG scale: 5.5, Seed: 1470082660, Size: 2048x2048, Model hash: c4da45e49d, Model: novaFurryXL_ilV155, Denoising strength: 0.38, Mask blur: 4, Inpaint area: Only masked, Masked area padding: 120, Version: f2.0.1v1.10.1-previous-669-gdfdcbab6

(5 fingers:1.2), (black pawpads:0.8)
Steps: 46, Sampler: Euler a, Schedule type: Automatic, CFG scale: 5.5, Seed: 4038320284, Size: 2048x2048, Model hash: c4da45e49d, Model: novaFurryXL_ilV155, Denoising strength: 0.38, Mask blur: 4, Inpaint area: Only masked, Masked area padding: 120, Version: f2.0.1v1.10.1-previous-669-gdfdcbab6



img2img: 
parameters

Prompts: masterpiece, best quality, amazing quality, very aesthetic, high resolution, ultra-detailed, newest, scenery, simple background, trio, 3boys, portrait, from front, full body view, (little anthro fox:1.1), (male:1.6), orange fur, young, very short, (short black hair:1.6), (fluffy thick hair:1.3), detailed black eyebrows, bushy orange tail, tail with white tip, ears brown, green eyes, (checkered onesie red and black), brown hands, (five fingers:1.3), paw with five fingers, black claws, open smile, (detailed canine teeth:1.3),

BREAK,
masterpiece, best quality, amazing quality, very aesthetic, high resolution, ultra-detailed, newest, photorealistic, masterpiece, best quality, amazing quality, very aesthetic, 4k, high resolution, ultra-detailed, absurdres, newest, scenery, intricately detailed, masterpiece, best quality, amazing quality, very aesthetic, newest,
---
BREAK,
trio, furry, full body view, (male, young), furry, anthro, little anthro pomsky, (male:1.6), (Grey and white fur:1.6), (short black hair:1.6), (fluffy thick hair:1.3), (dark gray ears:1.1), (detailed canine teeth:1.3), dark grey paws, detailed fangs, black claws, detailed thin black eyebrows, Heterochromia, blue and green eyes, smiling, looking at viewer, 3boys, abs, pink hair, fingerless gloves, toned, toned cub, looking at viewer,
---
BREAK,
"anthro, (furry:1.4), trio, 3boys, (male:1.6),
BREAK,
(young, young child, very young, kid, cub age, 9 years old), anthro, small body proportions, (short:1.6), (shortstack:1.2), little furry wolf, (grey fur:1.3), (wolf ears:1.1), grey and white tail, (aqua hair:1.2), short hair, (thin aqua brows:0.8), purple eyes, black claws, detailed fur, white countershading, white inner arms, (5 fingers:1.2), (black pawpads:0.8), 4 toes, white toes, black track suite
BREAK,
<lora:StS_Age_Slider_Illustrious_v1:-3>
<lora:StS-Illustrious-Detail-Slider-v1.0:4.5>,
masterpiece, best quality, amazing quality, very aesthetic, high resolution, absurdres, depth of field, newest, ultra-detailed, detailed eyes, detailed fluffy fur, dynamic lighting, 8k, HDR, ultra-HD, highly detailed, HDR, realism, realistic, realistic lighting, caustic shadows, (volumetric lighting:1.3), (cinematic lighting:1.3), complimentary lighting, (view from front:1.5),
BREAK,
Negative prompt: worst quality, lowres, low quality, bad quality, bad male anatomy, (female, girl:1.9), bad female anatomy, bad explicit, poorly drawn face, bad face, bad facial expression, ugly, bad hands, morbid, deformed, disfigured, mutilated, malformed, missing body part, malformed hands, bad feet, fused legs, broken legs, bad body proportions, gross proportions, disappearing hands, fused hands, fused body part, fused legs, (fused digits, missing digit, extra digit), bad artist, bad background, cropped, watermark, username, signature, not in perspective, error, jpeg artifacts, squares, blurry image, not in perspective, plain pose, plain figure, old, oldest,, (human ears, human), claws, long hair, girl hair, pony hair, visible penis, blush on snout, green hair, muscular, bodybuilder, muscles, (old:1.9), (adult:1.9), (teen:1.9), tattoo, human hands, (monochrome:1.5), (worst quality, low quality:2), lowres, bad anatomy, bad hands, text, error, missing fingers, extra digit, fewer digits, cropped, worst quality, low quality, normal quality, jpeg artifacts, (signature:1.5), watermark, username, blurry, speech bubble, text, monochrome, censored, nose, snout, (red eyes:1.9), background, logos, long torso, shoes, orange hair,
Steps: 36, Sampler: Euler a, Schedule type: Automatic, CFG scale: 5.5, Seed: 3783096032, Size: 2048x2048, Model hash: c4da45e49d, Model: novaFurryXL_ilV155, Denoising strength: 0.6, Lora hashes: "StS_Age_Slider_Illustrious_v1: bb11fa34470b, StS-Illustrious-Detail-Slider-v1.0: 2e7a68ec7e2e", Version: f2.0.1v1.10.1-previous-669-gdfdcbab6

[To generate images I used the program "ForgeUi" and for corrections and Inpaint]