FG400 on an Orange hexlogic pad is a pretty hefty combo.
I'd advise you are going to need to do some further refinishing work to remove the imperfections left by the first polishing stage.
A black pad and something like Menzerna final finish should do.
As for finish, I'd be looking at a sealant of some description. I've always found Chemical Guys Jetseal 109 with EZ creme glaze over the top works very, very well.