Whether to publish something on Vault or Moons is ultimately arbitrary and up to opinion. You cannot remove arbitrariness from this.
F2F52230B536214EF7C9924F483392993E226CFB G Pokemon - Crystal Version (USA, Europe) (Rev A) GBC
F4CD194BDEE0D04CA4EAC29E09B8E4E9D818C133 G Pokemon - Crystal Version (USA, Europe) GBC 
I did some testing and it seems to work just fine.
My guess is that you probably tried to link on both consoles at the exact same time. This will not work. There needs to be some time between when the first console tries to link and the second, usually a couple of frames.
This is because the first console to try linking will become the master time keeper. The second console will then be slaved to it, and will only send and receive data when triggered by the master console. When you try to link at exactly the same time, both consoles try to be the master time keeper, and cannot sync properly.
Ah, thank you. The link buttons are working in the console window, but the games are responding as if they aren't linked. Here's a savestate of three Pokemon Yellow games prepared to trade, which aren't successfully linking. I appreciate that you're setting up this feature that may only be useful for one TAS. Hopefully I can get it working.
Cable connect status:
LC: False
CR: False
RL: TrueAlright, thanks. Any suggestions on how to debug gameboy color games, outside simulating the z80 entirely?
Is it possible to record a TAS of three Gameboy Color games, with no more than two games linked at any one time? Either directly with the multi-disk bundler, or by somehow using a lot of movies that start from savestates in order to switch connected games.