Vanessa would probably be the best. She's hilarious and really down to earth and the least media trained, but has the lowest profile.
Una talks far too much. Seriously. She just rambles on and on and on and I'd imagine it'd be a bit cringey watching her on the show.
Mollie is sweet and innocent and I'd imagine she'd have a huge "Cheryl Cole effect" but really, she's just a pretty girl who loves pop songs. She wouldn't be comfortable judging others.
Frankie is far too bland, but has the highest profile.
Rochelle has a high profile and is the most confident so I'd probably pick her.