While I am currently engaged in a bloody war with you, I will answer your questions because I'm a pretty awesome guy in general...
1. Yes.
2. Right.
3. Random province. So, in Perpetuality, we are looking at a thousand provinces, so I think you can write that Banelord off. Bwa ha ha!!! He might be able to fight off the province defense of the place he lands in, but good luck ever getting home.
Also, I've seen some guys stay in Hell for over 30 turns, and I've heard that some guys can die in there, so don't get too attached.
As to your suggestions:
1. Life for a Life is Research level Blood 8 and has a fatigue cost of 199(one blood slave). When compared to other spells for other colors that do similar things (Frozen Heart at Alteration, Drain Life, etc), the cost to get into blood is very high already.
I mean, blood is the very weakest color and Research Path when it comes to fighting large battles. Just because my skill at blood magic is great does not change that.
2. Nah. Why would someone who has learned how to summon Horrors not learn to dismiss them?