It would ultimately become a he-said, she-said between Becky and Jackson on one side and Daniel on the other here, because while you're correct they certainly haven't contributed much, where's the documentation? And not just bank receipts, because with nothing in writing Becky and Cuckson will double-down on "we are a commune and we all contributed equally in different ways, not just fiscally." If Daniel wanted to fight THAT, he'd need a lot of evidence and I highly doubt he has that.
Without any kind of written contract here, it's back to stakes in the deed. They'd get 2/3rds unless Daniel secretly has a ton of money to throw at litigation I truly think his smartest move is to take his third of the equity and move on. He's not out for revenge like Becky is. He just want to get the fuck out as quickly as possible.