Warrior cats

Well I''m very much into animal fiction about non-completly-ridiculous stories. So lately the warriors series have caught my eye. I've been reading and have some questions I'd like to ask:
1) How many sagas are there? (like warriors,new prophecy, ect.)
2) What book do fireheart and tigerclaw become fire star and tigerstar?
3) Ill find out soon enough but if you read this before I do does Sandpaw become Sandstorm?

I know I sound like an idiot but Im really curious so please tell me if you know! THanks!