Are we allowed to put up a project, do devlogs, and release daily builds, or do we have to keep it under wraps until we have a finished project?

I think that you can choose.

I would assume its fine. good way to get people to playtest. 

both...gamer

I've literally done an open development here:

https://itch.io/jam/brackeys-4/topic/908543/play-testing-circle-come-play-my-game-ill-play-yours

with daily updates and daily builds