Arcaea will probably join the team victim while GA joins the team aggressor. OW might join the team victim.
OW could go either way, really. Probably more likely to join Kindara/Zonasa, but they might stay out of it. I don't think it's likely that they'd join Cathay, but stranger things have happened.
Arcaea I assume will eventually join Cathay.
GA might join Kindara/Zonasa, or they might just ignore the whole thing.