Castro made it into the third debate, making for ten candidates. Steyer only needs one more poll and Tulsi needs two more before the 28th. I don't think anyone else is going to make it. Marianne and Inslee have the donors but no polls, Gillibrand needs 20,000 more donors and three more polls. Everyone else needs both.
If they do get to twelve, I'd maybe consider splitting it once last time, six and six would give everybody more time even if it would still avoid MATCHUPS the media wants.