Before looking at the failover settings, you should check the base configuration.
If you rename interfaces, use the EXACT names you chose everywhere:
set [ find default-name=ether4 ] name="4.TPLink AP"
is not the same as:
add bridge=LAN ingress-filtering=no interface="4.TPLink"
internal-path-cost=10 path-cost=10
and
set [ find default-name=ether5 ] name="5.Ethernet"
is not the same as:
add bridge=LAN ingress-filtering=no interface="5. Ethernet"
internal-path-cost=10 path-cost=10
See point #21 here:
The *B here:
add bridge=LAN interface=*B internal-path-cost=10 path-cost=10
is an invalid entry, leftover from some edits.
About scopes/target scopes in routes, I personally find easier to use and remember 10/11/12, see: