Call me a fan of starting small, with the basics and optimizing from there.
Your central AP/ router only needs
option wds '1', not more, not less.
For the client, starting from a default setup, e.g. firstboot:
- stop/ disable dnsmasq/ odhcpd (configure it accordingly so even if started, it will ignore your
- reconfigure one of your wlan interfaces as client device, with
option wds '1'
at this point you repeat your signal to the client's ethernet (lan-) ports, don't do anything else (leave the switch configuration alone, unless you really, really, really need a fifth LAN port, you can keep the firewall running - it won't interfere with inter-
lan traffic), keep it simple.
- once you're there and tested, add (repeated-) AP interfaces to your client.
Basics done and working.
Now you have to decide, do you want the a single merged ESSID/ broadcast domain (for which IEEE 802.11k/v/r makes sense to set up) - or do you want a dedicated ESSID (probably nice for the initial testing, but once confirmed working the merged ESSID usually makes more sense).
Specifics can follow, if (really) needed.