Best / Simplest MDM for Small School? (NOT 1 iPad per student)

What would be the best (and probably simplest) MDM to use for iPad management in a small school that does not have (and will never have) one iPad per student? We began looking into Apple's MDM solution since we already use OS X Server for our Mac user accounts, but almost immediately it became clear that this is for configurations where there is one device per student. First, this will never be, financially, an option for our school, and two, we have no intentions of pestering parents to setup special Educational Apple ID's for their children, even though Apple does send a nice little email. That's just intrusive.

We could keep using Apple Configurator, which works fairly well for us, but it does not allow for a number of important things such as tracking iPad locations. Additionally, it's clear that Apple is in the process of abandoning Apple Configurator support (many Apps can't even be purchased via. the VPP program using downloadable codes anymore, and thus we can't even use those apps.)

Our needs are extremely basic:

Once enrolled via. the MDM, we would like to be able to wirelessly:

Push App updates va. wifi to each iPad

Install Apps purchased through the VPP program

Set iPads to Single-App mode when needed (state testing etc.)

Track iPad locations so that if one "wanders" out of the building we have at least some chance of locating it.

Change some basic settings if necessary.

Anyone had any luck managing these things an educational environment when you can't meet Apple's "ideal" 1-device-per-student requirements? If so, how are you doing it?

Thanks!