Actually if you can get one working, can you reflash the firmware to 200.6.x? While that is happening make sure the other AP is unplugged. Once that’s done .. don’t configure it yet, unplug the one you just flashed and plug the other one and see if you can get that working and reflash firmware to the newest of the 200.6.x series. Please make note of which version of firmware it has before rolling back to older firmware. My guess it is on some version of 200.7.xx but make note which version.
Once all that’s done just plug one of the APs into the switch and configure using a laptop. Once configured and rebooted and is working fine with the ssid you configure plug in the 2nd AP and it should auto configure it fine. I believe there is a bug on 200.7.x I experienced that one time on my r710 but I thought it was a fluke since I was testing out 200.7.x but when back to 200.6x for slow WiFi issues with iOS devices.
See if you can get one configured and flashed back. I’ll see if it is possible to flash a firmware in CLI mode even before configuring unleashed ..