Thank you very much! And...
Be more specific, what exactly do you mean? The maximum stack size?
Yeah, the max size.
Again, be more specific. You want to change how much damage mobs deal? You can do that either using the attributes system (SharedMonsterAttributes.attackDamage) and using EntityJoinWorldEvent again or if you need more detailed control using LivingAttackEvent.
Ahh, and how would I modify the arrow damage of skeletons? It's usually a different thing you have to modify right?