Good luck and have fun.
I can't comment on the suit question, but regarding shoes, a pair of Redwing Gentleman Traveller boots would be a good choice for the type of outfit you are wearing: jeans & wool coat.
A few years back I spent NYE (total of around 4 days). I only wore my Redwing boots through that entire time. I walked through snow, ice, puddles of water...etc. No problem.
I did Sno-Seal the heck out of my boots prior to first wearing though.
a Frog? I've got no suggestion for that, other than buy what you really want.
As far as sterling silver buckle, avoid at all cost ones from Ralph Lauren and Brooks Brothers. They look cheap, feel cheaper, and are not even functional as far a cinching the belt.
Best bet is to go with Tiffany's