Thea is S3/S4 of Arrow and Caitlin is start of S4 for Flash so both are pretty far behind her - though Caitlin has met her at least!
I don't think any of mine with memories have been in a game with a Kara there.
Her and Allison will definitely get along well I think though! Which is why I ended up tossing her there because I have been waffling on where to put Allison lol