I'm British and I think 4th Impact are ok (but just ok), and I *don't care* about their ethnicity
I don't know how far they will get in the competition, but I don't think they are going to win because I don't think they are versatile enough
Give them a mostly shouty / attitude / rappy (although I think their rap is meh) song that they dance about to and they shine (as they did in their first audition), but anything with a slow section where they have to try and convey a bit emotion just highlights their limitations