Surely these days the trend is to IP based solutions not speaker cables to a central location which is a bit 20th Century? I'm not sure that clustering 6 devices and 6 amps is going to work all that well. Unless you put the devices onto the wired LAN they are going to fight with each other for WiFi bandwidth. In fact I would go as far as saying that it would only work properly if it was wired to the LAN.Yes the WiiM’s will be able to hear one another as they’re all in the same cabinet, so hopefully they’ll all be in sync. I just need to find a remote control solution. I’ve looked extensively at whole home audio systems with inwall controllers that accept remote control input to activate the zones and control volume etc, but they’re mainly US supplied systems, and the inwall control units aren’t that elegant…. If you know of anything I could consider that’s available via UK suppliers I’d be happy to hear about it.
As to remotes there are some quite elegant wall mounts for iPad's and other Tablets and if you know what you are doing these can be locked to one app.