Can an OBi1062 use an OBiWIFI5G?
There are two issues:
1. Will the 1062's firmware recognise and configure the OBiWIFI5G dongle?
Probably. I have an OBi1032 which usually connects via an optional plugin OBiWIFI 2.4 GHz dongle. I unplugged that and put in the 5G version. The phone booted and connected to the 2.4 GHz Access Point as before without any manual intervention. I then used the phone's SCAN option and it saw the 5 GHz Access Point. However despite many attempts using the on-screen menu, the OBi's on-board web server GUi and the portal Expert mode I could not get it to associate. Always "authentication failed". Eventually, though I don't know how, I did succeed.
The 1062 and 1032 take the same firmware. My 1032 has 5.1.11 (Build 4858EX.1311)
2. Can a 1062 be configured to use a USB Wi-Fi dongle in preference to or instead of its built-in Wi-Fi?
I have no way to try that.