May I ask why they aren't a thing? Because me and my friend are interested in running it.

If it interests you, make it a thing!

Reasons off the top of my head:

You have to share already scarce resources. All enemies have buffed stats in multi-mode; additionally, their set-damage attacks are even stronger, increasing the max HP required to not get OHKO'd. Increased EXP might help mitigate this somewhat, not really sure. Tiny screen and lag.

Co-op runs have historically been online and quest-based (Ultimate mode quests with endgame gear / Challenge Mode).

Hm ok thats really good to know we are planning to use dolphin netplay to run any% epi1

You could consider finding a gamecube server instead of using netplay, that way you both have full screens to yourself. I'm not really that knowledgeable about the online gamecube scene these days but feel free to ask if you have any trouble.

The thing about doing it on a server is the chance of getting banned for exploiting

I've never heard of a single gc server banning anyone for anything outside of repeated FSODing

Hello, I had a question about one of the replies in this thread. MT, above you said "if it interests you, make it a thing". What would one have to do in order to get the Co-op category approved? My friend and I are actively planning a co-op run and I wanted to make sure we take the correct steps. Thanks for any info you may be able to provide.

Just do a run, then ask for the category to be created so you can submit it. I guess it won’t necessarily be created even if you have a run to submit, but I’d say that’s the first step. An empty category is not gonna be created so you need to show a run for it first.

Thank you for the info. We'll get a run finished and see what happens!