I'm setting up polls on the league page so everyone can have a say in some of the league settings.
Trying to be too democratic could lead to issues. If people join the league with a vision of what they want (no IDP), but the league decides on something else (IDP), then you risk having those guys check out mid-season. If you establish the rules, roster sizes, keeper status etc and post those on here, I don't think you'll have a problem getting 12 guys that are willing to play, and will stick around throughout since they know what they're getting into from the beginning.
Create the league you (and supreme) want, and then give everyone the option of joining.
I'm in know matter what, I'm not really concerned about what the rules are.