Currently running on 1.12.2-1.2.3. When I give a zombie a set of armor, only some of the stats are transferred. I can safely say that speedy works, but other effects, like sticky, don't affect players when hitting the mob. The invigorating trait of Knightslime also doesn't raise the health cap of mobs. It'd be nice if you implemented support for mobs using all of the armor modifiers.

Unfortunately this was a change made early in development that I've forgotten the reason for and now it's too entangled into the mod to change back easily without major refactoring. I'll look into this for the 1.13+ port but it won't be available in 1.12.2.