I think thats an excellent idea.

I dont know if I should say the name of the site (bleep it out if I can't) but JoeCustoms.com does this group project where members have to make a custom figure, vehicle or diorama based on a theme that everyone votes for, then they showcase everyone's work.

So picking out a theme or a figure to photograph is an excellent idea to get people to do an engaging activity, and Id definitely be up for that