mm I think Kyle would be a bit at disadvantage in the sense that he could not lose his temper as he usually does with Cartman. If he throws hands at Erica then he'd be seen as evil, no matter what Erica has done, because she's a girl. So Kyle's personality would have to be slightly less snappy for the dynamic to work. I think a good reference is Haruhi and Kyon from Haruhi Suzumiya, except this Kyon is angrier hahaha. When I rewatched the anime I kept thinking they were het Kyman.
From Cartman's side I think her attraction would be more obvious because (heteronormativity) it's more socially acceptable for a girl to like a guy than for a guy to like a guy, duh. So her teasing would be less confusing.....to everyone else, of course. For Kyle she's still an obnoxious girl that likes to ruin his day and he has no idea why.
so yeah I think their dynamic might mellow out a little because of gender/society lol but that's what's interesting about putting Kyman in different dimensions! The core stays the same but some outer components are changed