, 90-100 pts? You did have fun
Now for your questions.
1. In my opinion, all you can do is what you have already planned to do - stay at the low end of the points scale and get regular exercise. You may register a gain, but it won't be the end of the world, and you can "take the hit and move on", as a wise woman once said.
2. When I achieved lifetime (for the second time) last year, I thought that any deviation from the way I'd been eating would result in a big jump at the scale. Gradually, though, I learned that if I exercise regularly, I can eat a substantial amount of food and not gain weight. I don't know the exact number of points, but I know it has to be in the vicinity of 40 - maybe more. As a result, I don't really feel the need anymore to have blow-out days like I did in my previous weight-loss struggles. Eexercise has made the difference for me; I don't know if others have had some same experience, though, so I would be hesitant to recommend this approach.
Good luck with your weigh-in.