Disabling network connectivity monitor - Must be enabled for mesh to work
Using manual meshing and specifying priority APs so as not to overload the primary AP - Good idea
Using DHCP for these APs rather than my preference (static IP) - Static is preferred to prevent DHCP timeout
Assigning different channels to each of the devices to reduce interference - All downstream Mesh APs must be on 5G AUTO or match their uplink partners channel. Use manual non-overlapping channels on 2G for all AP
Upping the radio strength to high for the 5 Ghz band - Good idea during testing
Also, SSH into the AP and look at the logs. IIRC they are in /isolation_logs/