They released FP for the new Frozen ride, Soarin, and the new Jungle Book show at AK. Then they changed FP booking from midnight until 7am the next morning. System is still recovering. Did you try logging out and back in? Sometime just give it until the next day. It's a mess right now but...
1. Nothing as far as what's already booked. It remains booked.
3. Always a good idea.
The system going down just means you can't change anything until it's back up. Sometimes all your stuff will disappear when the system is down but it shows up again as soon as everything's working.
Remember the new Early Morning ticket is on Tuesday and Saturday mornings. Only people with those tickets will be able to ride or get in line until 9am. There will probably already be a line from the early morning guests. I would get a FP myself.