Just to update:
IMPORTANT:
All team members must have an IP address assigned to their LAN port.
This must be done even if the LAN port is not connected or not used in your setup.
The DHCP server feature is not supported when controller teaming is active, therefore an
external DHCP server needs to be installed to support dynamic addresses assignment to
controlled APs and their users.
APs do not have to be located on the same subnet as the team, but can be connected to
the team via an L3 network. However, all APs must reach the team on the same interface
(port, VLAN, etc.).
If the APs are provisioned for controller discovery, than the APs must be provisioned to
discover all controllers in the team, not just the team manager, otherwise failover is not
supported.
Multiple teams can be installed on the same subnet.
To successfully support controller teaming, the network that connects the controllers
must not block TCP port 4999 and UDP ports 4999, 38215, 51936.
The networking settings on each controller must match. If a VLAN is configured on the
Internet port of one controller, it is automatically configured on the Internet port of every
other team member. The switch ports to which controllers are connected must be
configured identically.
Public access
Customization of the public access interface web content should be done via attributes
retrieved from a third-party RADIUS server. If RADIUS is not available, you must
manually configure each controller in the team with matching settings.
Payment services are not supported.
Users
Wired users are only supported via the MSM317 switch ports. Wired users cannot connect
directly to a team via the LAN or Internet ports.
The local user accounts do not support subscription plans when teaming is enabled.
Accounting persistence is not supported.
This is from page 8-6 of the manual
The GMS is also not supported on teamed controllers