[BUG] Heads have strange / incorrect textures, incorrect placing

[chmonyasik]

Describe the bug
Some heads have strange / incorrect textures (the bat head, for example), and / or don’t properly attach to the wall when placed on a wall instead of the floor.

To Reproduce
Try placing the heads on a wall and check whether the texture is correct and how closely they attach to the wall.

Expected behavior
The heads will have the correct textures and will properly attach to the wall when placed on it.

Version information
Spectrum Version: spectrum-1.12.7-1.21.1-neo
Minecraft Version: 1.21.1
Mod Loader: NeoForge 21.1.250

[DaFuqs]

1. The Bat head does lack the ears!
2. The other models look fine for me. Maybe a case of [Feature] Support for custom mob models #928 where some mod ships custom mob models, including overriding the vanilla textures?
3. The wall offset will need some work, since the models differ greatly in size.