Far, far too late... here are the results and levels!
In second place, earning 12 chip cup points... Dave Varberg with Splitsville. It's a level on rails, and the dynamite and dirt boots don't matter. The split screen isn't used to great effect either, as the level really doesn't request any simultaneous movement.
And in first place is H2O with Split 1, Split 2, Split 3 and Split 4 with 15 chip cup points. I'll briefly summarize each of these before revealing my favorite.
Split 1: This level boils down to a simultaneous run where both characters must follow a mirrored path from each other. I like this idea, though it's a little stricter than I'd like for a one player splitscreen level and much simpler than I'd like for a multiplayer splitscreen.
Split 2: This one is all about simultaneously (except if you're within a few ticks, the chips turn back into bombs) pressing 2 green buttons. Not too interesting but a nice concept. I find myself wishing these levels were combined into one...
Split 3: Nice little avoidance puzzle! Both players have something to do and I like the layout- this one really can stand on its own. I didn't find a use for the teleport, though I didn't find myself minding either.
Split 4: I feel like this one would work better as a single player level- each player is off doing their own puzzle- Chip has to move a block quickly to redirect a fireball, while Melinda has to... dodge a tank and remove two locks to have a glider reverse a force floor after Melinda finishes. I like the ending mechanism here, it's quite clever, but I don't think the level being splitscreen adds anything new to the table.
So Split 3 is my favorite and the winner!
What would have been really cool to see that I'm only just realizing would be: a "normal" variety level or open ended type level except there are two players for division of labor, or shortcuts, or any number of things. As mentioned, some sort of minigame or even a competitive subgame within CC2 could also have been really cool- something to bring out the multiplayer part. It might be cool to play through, say, CCLP1 Splitscreen Edition. Or it might be a terrible idea! Who knows?