it's very unlikely it wasn't Soy. Soy is drunk and/or high a lot of the time he is online so I wouldn't take all his statements as 100% accurate. When he said he hadn't played for months, he was still logging in and playing occasionally. It's just that he basically gave up on MWO after his last temp ban. However is the type of guy that if he promises to help out with a team then he would log in to drop with them for a comp match. Therefore I'm pretty sure it was Soy in all those matches especially considering the only mechs he used just happened to be the only mechs Soy has used for the past year (ARC, NVA, TBR).

Soy sharing his account and offering to give it away was not exactly a secret. He had posted pretty openly about it in-game and on twitch even before his previous ban. However I still don't see any good reason why someone would bother to use his account for MRBC. Someone could have tried doing it to get around the 1 team limit but really the motivation among the top tier players to even play this season is so low right now that I can't really see many players even wanting to play for 2 teams anymore.