Awesome work. And I'm sure they'll be put to good use, ridden hard, and produce many smiles.

A couple thoughts on your above points:
1) Marymoor is a shallow banked track. You can get away with lower BB's on MV that would put you on the boards sideways on most other tracks in the country.
6) I've been using water slide decals from Gus Salmon (find him on FB). Very thin, easy to clear coat over with rattle can clear on powder coat (or provide them to the painter if going with wet). He can do great things with graphics, and specializes in reproduction graphics.