The rules do not state if dying during a co-op run is permitted, which if it is, then the meta could just be that it's a solo run with a dead person just being there

I will message the other moderators about this and let you know what they say.

I think that a good idea could be limiting the time or amount of deaths a coop run could have. I believe a better system for the run would be to find the amount of time a player was dead vs alive, and if it surpassed a certain percent, then it would be invalidated. Only issue with that is that would murder the mods tryna track that. So another idea could just be checking how many times a player died, like limiting it to 2 deaths per run. Idk just some ideas i wanna spitball.

Seems overly restrictive, if a co-op strat involves people dying, then I don't think there should be an issue with that. Though deathless could be a great subcategory

I think it kind of defeats the purpose of co-op, since allowing deaths would (as stated above) potentially turn it into a solo category with people who's only role on the team is to die. Plus there's no reliable way to track dead vs alive time during a run. If there is a glitch that involves dying I think it could be a cool exception in the future for the glitched category though.

EDIT - It also takes away the potential for clutch moments where you save teammates from dying since just letting them die will pretty much always be faster (unless they're carrying good items).