This is something that should be in minecraft by default, but it is something that they probably will not do (which they should) I like a lot, although if they had been 3 pixels in the arms even more, although it may not be possible, I still like it

Can you make a version so that the skeletons don't have hair?

I dont think the skeleton alex is that necessary because both male and female skeletons in real life look the same. But this pack is really cool!

Girl sounds for zombies, husks, drowneds, skeletons, strays and wither skeletons please?
Since Alex is a girl.

On the 3-pixel arms topic: I recently got into Blockbench and one quite easy solution would be to just add the 3-pixel arms to the model and include the associated texture in the texture file in an otherwise free spot. This way you get a model that has both arms but only those that have a texture included show.
I just tried and it does work, however there are some limitations I can't figure out yet. For one, drowneds use two texture files, but the custom entity model only seems to apply to the inner layer, meaning that the outer layer, which is the most visible one, still uses 4-pixel arms only. Secondly, all items the mob holds still get placed according to 4-pixel wide arms, notable with chestplates and tools/weapons, though probably neglectable.
The ideal solution would of course be different models for different mob variants, but as far as I've seen so far, OptiFine doesn't seem to support that, sadly. Does anyone know of a way to accomplish this?