First thing to keep in mind is that this room, by its shape and choice of surfaces, is acoustically compromised for worship. It looks like it would make a great classroom, not so much a worship space. Since you're starting out compromised, there's not a lot you can do to make it sound "great."
Not trying to discourage you; just trying to make sure your expectations are realistic.
A well designed overhead center cluster will probably provide the best sound. It usually does. The room is small enough that coverage shouldn't be a problem.
The cluster should be over the front edge of the stage if possible. Having speakers behind mics is a recipe for uncontrollable feedback. As it is, with the size of the room, your "talent" will need to stay pretty close to the mic to keep feedback at bay.
With the low ceiling, you will have to have a really low profile cluster. If you go with a cluster, you may have to move the projector & screen. Moving the projector & screen to one side will make it more difficult for half the room to see (unless you go with two screens or turn the screen inward slightly.
If you go with two sets of speakers, be aware that there will be comb filtering in the center of the room that will make it sound wonky. Don't try to do anything in stereo, because most of the room won't hear a proper stereo image.
Young folks can be pretty energetic (understatement of the year, there) and keeping volume levels low will take some strong discipline. The principles behind Mike Sokol's "semi-silent stage"
will be important for keeping stage volume under control and, therefore, a clean mix and good coverage.