Indeed. Each could solicit pictures over a period of 2-3 weeks. They create a roster of the best five and then go head to head.
I also like the idea of other team based challenges. Maybe bi-monthly. Team @Murlsquirl and Team @Cleav those who want to play can submit themselves to a (not public) draft to create rosters. Some challenge, the teams submit their three best fits, then vote. Maybe make a season of it with 8 challenges Dec-Mar all...