@jst-2405 

At a minimum you want 2 wired units, even if that means you have 5 APS... two wired at the same location, and 3 remotes that are wirelessly meshed.  You may also wish to leverage a dual channel strategy, so consider two wired nodes W1 and W2 and three meshed nodes M1, M2 and M3.  You could configure them such that say W1 and M1/M2 are on Ch149 and W2 and M3 are on Ch157.  This will double the amount of backhaul capacity you have, and in the event that either W1 or W2 fails, the Mx devices should eventually rediscover the remaining wired node and rejoin.

Be aware that if the mesh needs to 're-converge' it isn't fast or seamless.  It could take a minute or two from interruption until working again.

Meshing uses the 5.8G channels and I suggest you limit their use for backhaul only, and enable the standard 1/6/11 for the access.  However, you may find in practice that a million or so (usually Apple) devices are generating so much noise in the 2.4G bands (looking for wifi to jump on) that those channels become unusable for hi-def streaming.  Once you've got your setup installed and working, I'd suggest disabling SSID broadcast to further discourage interference.