If it were me I'd wear slacks. They could have small pin stripes running up & down. Don't get circles. i think you could wear a vest, if you wanted to. I have never had your problem, meaning skinny legs & no butt. I am big all over as bad as I hate to admit it. Are you heavy or just have a big gut? A elestic underpanties could help with the gut problem. I have to wear a brace or binder and it does the same thing.

Whatever your confortable with will be just fine. Relax, the worse thing that could happen is that you part as friends. have a good time talking about memories and people. Keep ex----- out of the conversation. Good luck and enjoy yourself.
Hugs,
BC