OK, so weird rules question: how do you track commander combat damage for two commanders that each have partner and that meld with each other? When the melded commander does combat damage to a player, is that a third combat damage track, does it go towards the un-melded combat damage trackers, or does something else weird happen?

This is absolutely a strange rules question, since not a single card on Scryfall would seem to run into this scenario, but for Pride Commander, all commanders are given the partner keyword, so you can run into this case with commander partners like Fang, Fearless l'Cie and Vanille, Fearless l'Cie, both of which meld into Ragnarok, Divine Deliverance. Similarly, Gisela/Bruna.

Anyway, thanks for the help!