Unleashed APs look for an Unleashed network on the LAN/subnet they come up on, get DHCP/Def-GW for.
You can statically assign your AP IP addresses outside of the LAN DHCP server scope (recomended).
For any that you intend to use as Mesh, I'd suggest connecting those wired first, to be sure they are
recognized/upgraded(if necessary)/configured with Mesh info, before assigning static IP/Def-GW info.
I'm not sure how your HotSpot router with client isolation is configured network wise, but Unleashed APs
look for their Master/peers on the local LAN that they come up on.