Adam, to have the APs able to hear/talk to each other via MiNT level-1 (which is what would be occurring between APs local to each other) you just need to ensure that the connection points between APs allows Layer-2 Ethertype 0x8783 (just make sure they share the same management VLAN).
There's no need to have either an actual WiNG controller (hardware or VM) or even an AP configured as a VC (virtual controller) to make this work. These APs can operate as if their were old-school FAT-APs, completely autonomous (just means that any configurations has to be done manually on each AP, right?).
Even operating that way, as long as the MiNT mlcp vlan configuration option is enabled on the APs, they will discover and form level-1 MiNT links with each other. If you want to check this option, look at the running config. Run this command. You should see 'mint mlcp vlan' w/o a 'no' statement in front. If you see: 'no mint mlcp vlan' then that is your problem.
# show running-config include-factory |in mlcp
If it has the default settings, you should see:
mint mlcp vlan
mint mlcp ip
mint mlcp ipv6
In case you haven't already discovered it yet, you can check various MiNT connections/stats using different commands. Where I'd start first is with this one. This will confirm if an AP is able to discover the other APs via MiNT.
# show mint neighbors
If the result of this command comes up empty, then it means that the AP is not able to discover the other APs on its management VLAN. What I would do next in that case is see if you can simply PING one of those other APs (This presumes that they have an SVI configured with an IP that should be PING'able). If you can, then you have layer-3 connectivity to them. The problem then is with the layer-2 connection between them. That part, YOU will have to figure out. 🙂
When you say it shows the controller as a MiNT neighbor....you didn't mention until this point, but do you have an actual controller in this mix?