You can believe THAT the whole document is true without having a certitude about WHAT every single part of it means. The bible itself says that being a Christian is not that brittle. It says that a Christian can have incomplete knowledge, he can even have incorrect beliefs about some things, and yet he can still be a Christian, and he can trust that some day he will know the truth perfectly.
Yes, but if you are going to put your faith in a religious leader, as opposed to sola scriptura, it seems to me that a higher standard of the leader, is required. I don't like to work for a man who knows less about the job than I do.