Oh and how much can companions carry, and do they automatically use anything I give them?

Yeah, book bonuses give you one point per book permanently.

Additionally, I just got ED-E to be my companion, and Boone already is. I assume having 2 companions is fine and won't break or lose me anything? Mind telling me a little about ED-E, does he fight, does he fight well, etc.
Also thanks, thumbs all around.

I accidentally got 2 companions in addition to ED-E

I'd tell you about it but it involves a minor spoiler

Best part about ED-E is that you could offer him to the White Glove Society (well, I was able to)

Please, explain?

White Glove Society is a cannibal group that hides their cannibalism from the public

Thanks dude. Anyone mind giving me tips on Boone and ED-E? Should I keep their default weapons, like Boone's sniper, or give them something more fancy like a laser rifle? If I give them my spare laser rifles, will they have unlimited ammo?

Boone's Hunting Rifle is already pretty good, but if you want to give him a better gun, and I mean gun, like the sniper rifle or Anti-Material rifle, you need to put it in his inventory and atleast 1 clip of ammo for that weapon.

And you unlock his Loyalty quests basically by being a dick to the Legion.

Talk to boone. Get his loyalty quest thing done. He gets a bonus and better armor.

Spoken to him a load, not getting any quest-like responses.

As in the leader of Caesar's Legion? God no, just started the game yesterday. About level 9, heading to vegas for the first time.