Sammie/James
Acting as a single mum using his own as a template was pretty smart, and he played a "lovely young girl" quite well, until he started to slip. He'd probably have done better if he didn't amp up the gameplay.
Jay/Katie
Did she say she went in to find her son a girlfriend? Can't remember. But yeah, using "slang" isn't necessarily important in pretending to be young, just speaking in a straightforward way would be fine.
Busayo/Josh
I think her strategy was wrong tbh - everyone would have liked her more if she'd have just been herself, and no-one in there had much in common with a "gap yahh" type.
Jack+Beth/Joyce
Neither of them were smart enough to follow the story they crafted
On paper it's a good move to craft their profile to appeal to who was in there, but Woody and Ella would obviously ask them about it.