Magic- Is listed above, and while you can use all three types, doing so diminishes over all mastery of the categories, where as if you focused in one, you would obviously be more equip to master and progress in one form.

One character for now, but potentially be ready to make more if you wish to stay should your RPC die.

As for their strength, it states above that all players are "beginning adventurers of characters" so the players RPCs won't be over-board power-houses, but they will be decent.