Waking closed lid macbooks using wireless
Apple now says yes: https://support.apple.com/en-us/HT204032


  If your Mac supports Power Nap, these activities can occur while your Mac is asleep:
  [...]
  Mobile Device Management can remotely lock and wipe your Mac. 
  
  And these activities can occur while your Mac is asleep and plugged in to an AC power outlet:

Software updates download.
Mac App Store items (including software updates), download in the background.
Time Machine performs backups.
Spotlight performs indexing.
Help Center content updates.
Wireless base stations can wake your Mac using Wake on Wireless.



Assuming Power Nap is on AND the laptop cart is a powered one AND is actually plugged into the wall (yes, that one's from experience), you should be able to reach them remotely. Apple Remote Desktop does with 10.11 and 10.12.