Definitely have a back up plan w/respect to moving. You can't rely on your h to help you. If he gets a bug up his behind, he could very well tell you again that he won't help.
Also, you need to sit down and figure out where you are going to stay just in case you don't get the answers you need concerning the extension that was built. I wouldn't plan on moving into FIL's empty house, especially if you've not heard from him in quite a while. If the friend's offer still stands, I would take her/him up on the offer as it might just be for a short period of time.
You've got this...get your back up plans in place today.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.