I had some ideas what it could be analyzed from.
Most of them are from items/blocks that these animals drop or are bred with.

Hoglin
Raw porkchop, leather, crimson fungus

Strider
String, warped fungus

Mooshroom
Raw beef, leather, brown/red mushroom

Goat
Wool, in later versions goat horn

Bee
Honeycomb, honey bottle (or block)

Turtle
Seagrass. scute

Axolotl
Tropical fish, lush caves vegetation

Dolphin, Cat, Ocelot
Raw cod, raw salmon, tropical fish or pufferfish (just like Polar bear DNA)

Glow squid, Squid
Glow ink sac, ink sac, respectively

Panda
Bamboo

Wolf
Bone (vanilla)

Fox
Sweet berries

Cod, Salmon, Tropical fish, Pufferfish
Raw cod, raw salmon, tropical fish and pufferfish, respectively

Bat
Stone, cobblestone (I don't really know what to put here)

So the bee should already be that, same with the hoglin and raw pork, turtle should be acutes already,goat should already be wool and horn,and mooshroom should be beef. The rest we won’t do anything as it makes no sense to get dna from something that isn’t the creature.(squid’s maybe)