Second, it all depends upon the piece as to what parts you leave out, but you know this. You're a music educator.
What I plan on doing is picking pieces with a limited number of percussion parts, assigning kids to parts accordingly, and not rotating whenever possible. Two kids will play accessories (divvied up), one will play mallets, one will play bass, one will play snare, one on timpani. I'm not allowed to rotate within a concert (have to sanitize in between kids because of district policies) - so those kids who don't get to play "battery" will get first choice of parts in the Spring concert, as well as will be given a solo to work on to continue their development on snare or timpani.
This year is about making do, not doing right by everyone. It sucks for the kid who is going to play cymbals for an entire concert, but this is the policy I have to abide by.
With two, maybe three consistent kids? Snare, bass, accessories. Done. Don't even try to use anything else. Pick songs off the list that have limited parts. Your at home kids can play mallets.