Psh. Guy likes being around kids, for all he can be a deliberate jerk to adults. He would be the sort to keep ice cream at the bar for kids to make them milkshakes...SO LONG AS NOBODY TELLS ON HIM. I'm debating saying his bar is in NY rather than on Oa right now if that's OK by you, since it could provide some more plot opportunity then?
Whereas Guy talks too much and is a lot smarter than he lets on, but I could see him getting on OK with Cassie, given his abusive childhood and his working with special needs children. He can go easy on those that are more vulnerable due to the hand life has dealt them.
Well, if Guy is annoying PG he could run into Terra. And he'd probably think she's cute--look at him and Milagro. :D