Thought I would mention this for you guys,
Witch water can transform mobs
squid>ghast
pig>zombiepigman (haven't actually done this one yet)
skelle>witherskelly
adding in a bit of botania and that is how im making ender pearls with a squid spawner
reinforced obsidian is nice, i made 150 of it so now i have a 5x5 box to fight the wither in/hide inside if he gets an infernal ability that teleports him out (hoping to god that cant happen but that is why I built it 100 blocks away
ender io solar panels are nice ,ive nearly replaced half of the roof from the starting base with them and now I dont need to worry about power (as much)