Yes, it is included :)

Hm, I can't say more than "reset and try again" now either - but the Ubiquity forum on their website is very helpful, usually....

Whether/how depends on the AP that is currently in use. In principle, several APs can distribute the same SSID, but most mobile devices remain "stuck" to one AP instead of switching to another that would offer better reception. If only ubiquitis are used, the APs take over the roaming of the devices and you are always connected to the AP that offers the best connection.

What do you mean? You can either use 2.4GHz and 5GHz at the same time or switch off the other and use only one.

No, no, yes. By the way, the LED can also be switched off in the settings.