My answers:
Break a world record? - Nicky91
Go commando? - Benjamin
Have a threesome? - LT with two blondes.
Become a millionaire? - Niamh
Have their own Reality Show? - Jessica
Be killed first in a Horror Movie? - Anyone on the Forum that's black.

But getting away from that trope I'd say Alf.
Marry more than once? - This one's tricky, but I will say Parmnion.
Become Prime Minister - Joey.
Be late for work? - Can I say myself?
Plan a TIBB meet up? - Kate
Get drunk at happy hour? One of the Scottish members.

But seriously I will say Cherie.
Flirt with their boss? - As I can't say myself again, I will say Zizu.
Survive a Zombie Apocalypse? - Toy Soldier.
Fake their own death? - I honestly don't know, I'll have to come back to this one.
Join the Mile High Club? - The first name that entered my mind was Glenn, I'm sorry if I'm really off on that assessment.
Become a Stand Up Comedian? - Arista.