I actually amended the rules of challenging people today actually so you don't have to worry too much about this.
You need to amend the stagelist too... it's a travesty that Pictochat, with all its hazards, is legal, but Metal Cavern, a beautiful throwback stage with a unique design, isn't...
EDIT: Also, I'm of the opinion that instead of banning 1 starter and 3 CPs, you just get 4 stage bans... as an example, I'd rather not play on Battlefield in 3.Q purely due to concerns about freezing, but I'm definitely not playing on FD, and there's only one or two other stages I'd like to ban... so I'm stuck banning FD and crossing my fingers my opponent won't go Battlefield [although I do like Battlefield, it's just 3.Q problems] when if it was just 4 stages, I could use that ban on Battlefield and not have an issue.