Stonemaier licenses are not listed in the "available license" list on the dev environement, which means that the developpement will probably be done by a freelance developper, which is not necessarily easier than finding a volonteer dev for popular games :
- BGA/publisher want to hire a freelance to ensure a certain quality on the implementation, so that can restrict the pool of available developpers
- freelance work implies deadline, not all game developpers are willing to deal with them, and some of them might be already busy with other work (which is my case for instance)
- freelance work means money, so BGA/publisher also need to find a freelance dev with a quote matching the amount they are willing to invest, which might be not that easy with complex game that can require a lot of dev time
- complex games requires lot of dev time, so some of them might be already on their way
In any case, as junibegood said, the projects will probably be developped in "ninja" mode anyway on the dev environment (kind of a private alpha), so you can't know for sure which ones are already under developpement or not.