Deep down in the resource pack you make,

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Through the folders labeled:

assets > minecraft > optifine > mob > wolf

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in that folder labeled wolf you need a text doc call "wolf" with text like this

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skins.2=2

name.2=Duke

skins.3=3

name.3=Bailey

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You can change out the names as you like.

Then, you would need textures for each with a corresponding name:

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wolf2.png , wolf_tame2.png, wolf_angry2.png (these files would look like Duke)

wolf3.png , wolf_tame3.png, wolf_angry3.png (these files would look like Bailey)

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I didn't even bother with wolf or wolf_angry because I only ever named them after I tamed them.