Rinne tensei will cost you your life i believe, and maybe he didn't know the jutsu yet.
no, it only depleted his chakra reserves after he had practically used all of his chakra that day and he did revive a lot of people. if i remember correctly Konan said to him the way your chakra reserves are now, or sth similar.
so, no. it wouldn't kill him. but probably there is sth like a time limit after which the jutsu is rendered useless. or sth else, kishi will soon tell us as in order to revive Madara with rinne tensei as the original plan was, Nagato would have to use the jutsu long after Madara died.
maybe it is sth like that: rinne tensei can either revive a lot of people simultaneously but close after their deaths, or one individual and long after his/her death.
either way it is weird that Nagato completely forgot about Yahiko and decided to save the jutsu for Madara.
said plot hole has been pointed out before, and it bugs a lot of people... on the other hand the way the story is right now many things could bug a lot of people