First: I think you will have a problem with client mode of at least some of your devices..
My guess is:
You will only be able to put your 2.4GHz radio either in access point mode or in client mode, but not in both at the same time. The same holds true for your 5GHz radio.
- You can put your lower right access point in access point mode for both, 5GHz and 2.4GHz.
- This means you need to put your lower left access points 5GHz radio in client mode. This, in turn, means your lower left access point will only be able to send out 2.4GHz wireless itself since its 5GHz is used ab for the connection to the left.
- You can put your both upper middle access points in access point mode because they are cable wired.
This means they will both be able to send wifi out (SSIDs default, guest and limited).
This means you need to put your upper right access point in client mode.
Which, in turn, means the thing that is labeled "external" will not be able to provide 2.4GHz wifi itself since the 2.4GHz radio is used up for the client connection to the left.
Do you see the problem I'm trying to explain here?
Second: vlan tagged wireless uplink
My guess is: That's doable, but it will break your neck as for using the script Catfriend1 provided because 50% of that will not be covered.
Let's assume you have a single "vlan aware bridge device" "br0" which is briedged to eth0, so you have br0.1 for LAN and br0.2 for WAN.
That should by close to default settings after flashing OpenWRT. If not, that's what you can easily configure.
Going from your lower right AP, you can set up four different SSIDs: "default", "guest", "limited" and "external".
Let's put them on VLANs 1, 3, 4 and 5 (because vlan 2 is traditionally used for WAN).
So SSID "default" is connected to br0.1, "guest" is connected to "br0.3", "limited" is connected to "br0.4" and "external" is connected to "br0.5".
You can set up a fifth SSID "trunk".
Instead of binding br0.1, br0.3, br0.4 and br0.5 (those interfaces used for the other four SSIDs) to "trunk", you could simply connect "trunk" directlry to "br0".
This will make the "trunk" SSID transport every vlan.
It's mandatory to use a bridge device "br0" instead of directly going through "eth0".
The same goes for the reverse direction: Make a wifi client on your lower left AP connecting to "trunk" and bind it to "br0".
Now you can go wired br0.1, br0.3, br0.4 and br0.5 on your lower left AP.
Once you've done that, you can set up a 2.4GHz wifi on your lower left AP exposing "defaut", "guest" and "limited".
But as I mentioned in my first section, 5GHz will not be available for providing AP wifi because the 5GHz radio is in client mode.
My overall suggestion is to drop the idea of a wireless backbone for multiple SSIDs and run wires from one AP to the other. You can go default "dumb AP" documentation from there and use the script Catfriend1 provided.