Skye would probably interact with Thomas more since she's dating Gawain (and friends enough with Wil) possibly? And Trish has loose connections there because they were on Quidditch together. My other non-Slytherin 7th years could probably talk to him some more too.
With Georgia, we could always do something with her and Emma? Emma is pretty closed off and really only considers Ophelia to be any sort of a friend other than Sep, but I assume with them living together for so long they'd have had to have real conversations sometime. So she'd just change her behavior when Georgia is being all flighty to that 'just deal with it' that she's been doing so far.
Aaand for Dirk Marlene should probably be his friend on some level. They're both prefects, I believe, since we got that all fixed. And same house and year and all. Might even be able to get Trish, or Viv once I write her more other than with her siblings so I can figure her out more.