Versions below 1.16 have a problem when armor stands stand in a block. They appear extremely dark in this case. 1.16 seems to fix this issue but it exists in other versions. I've fixed this for these mobs except the great hunger because it's too tiny. Make sure to use 1.16 for the best experience!
I've also fixed the random spawns.
If you encounter any more errors, feel free to ask for support on my Discord ( https://bit.ly/XMobsSupport )