What about Tweek x Christophe (le mole)?
I think the ship started in Hell Park and is not as popular as the Creek, Twenny, or Tweek x Pete.
I don't know how that would fit in, but I imagine something entertaining like the ex creating an interrogation of Craig to see if he knows Tweek well.
Hooooooooooooooooooooooooly shit. Dude, I am so sorry it's taken me this long to reply. Still, better late than never, right?
On to your question: Tweek and Christophe. It has been literal ages since I last watched Bigger, Longer, and Uncut, but I definitely remember Christophe. Probably the most interesting one-off character in South Park history, in my opinion!
As for a relationship between them...well, I can't say it would be all that good of a romantic relationship. I don't really see Christophe as all that interested in romance, jaded heretic that he is, but I could see an interesting friendship between these two. It's an interesting dynamic to be sure.
I figure they would have, at most, something relationship-adjacent. Not exactly friends with benefits, but something in that neighborhood. The sort of relationship where is a definite bond between them, and they clearly care about each other, and while it seems to go beyond the feel of friendship, it veered off from romantic and went into some sort of undefined no-man's-land.
Christophe's complete and utter disdain for God and his disillusioned worldview both jives well with Tweek's...Tweek-ness and conflicts with it in a way that makes for a surprisingly interesting dynamic. It's canon that Tweek has looked into beliefs, views, and philosophies that attempt to reconcile the mortal and the divine (specifically his interest in Buddhism), so pairing the guy with little (if any) control over his own life with the guy who's probably in a similar boat but has decided to make peace with it by not making peace with it? Yes, please.
These two are the sort of duo I would LOVE to see in a post-apocalypse situation, because I think they play into each other's strengths and weaknesses well enough to not only survive but to actually kind of thrive.
Now, in terms of Creek our beloved, I could absolutely see Christophe has playing a mildly over-protective role in making sure Craig is good to Tweek. God is the biggest bitch of them all, but He's got nothing on Christophe if he deems Craig unworthy. And it's not so much about worthy or not, it's more about Christophe caring enough about Tweek that Tweek's long-term happiness (if there even is such a thing) actually means something to him.
It's an interesting dynamic, and I apologize if absolutely none of this makes sense. I used up most of my weekly allotment of written coherence this morning at work, and it takes a few days to recharge.