What are costume bindings?!? lol
Anyway, yeah I wouldn't buy the cheapest bindings Burton makes. The Custom or any binding OTHER than the freestyle has a proper toe cap instead of a little old toe strap.
Also, you don't need rocker to ride switch and jib. If you're set on your board choice, go for it, but being brand new you might want to look into a flat board instead. It's the middle ground of everything so would likely be good to learn on.
Alternatively, buy a used board and use it for a season or two. By the end of your first full season you'll likely have a much better idea of what type of riding you love.
Just my $0.02 of course!