Okay I know this shouldn't be a Gripe,but... Dude... It's not batgirl... It's Robin... She's still Robin DX
lol, but anyway...
Yeah I had Robin with Kid Flash because they pretty much = Best Friends. Essentially. Which would mean they work well together Albeit a few jokes and what not. 

I wouldn't mind moving Rachel down though. I think her, Sayaka and Superboy would do well. And I think it might still be fine. or switch Sayaka... Still overall those who would know each other best would probably be KF/Robin or KF/Superboy. Not sure on how well Rachel knows Robin, but meh.