@ BeccaVengeance
Totally loving that idea. Also I think the girls will be strangers and some of the girls might clash, whilst others bond. I know the way I have made my character, she doesn't tend to have many girlfriends and apart from maybe having a good bond with your character, she tends to stick with the boys (minus Harry of course).
I think because Niall comes across quite timid and less forward when it involves girls, like with your OC it could be a matter of him being scared to take things further- so such as stuck in that friend zone despite you both being smitten with each other, sort of thing. That's just one idea!
I'm still unsure how these girls can get entered into this test. Like perhaps some put themselves forward, one is put in for a joke from friends and then one puts there name in hoping to get one boy, but ends up with someone else- that's how we could create a girl who is with one guy but crushing on another.
With the house idea, perhaps at the beginning they are put together in a house to bond and get to know each other, but for some it can get too intense and a lot of drama happens. But if they are under one roof, they're allowed out and Simon encourages them to be seen in public together since that's the whole point- bettering their image. So they can go to events and such to boost their image.
These are just ideas and I'm just trying to make sense of some things, so please people, let me know if you have some ideas