I haven't bothered using the using the BLtouch either. I just homed and manually leveled the bed using a piece a paper for now. But as aardvark mentions, the Bltouch should definitely be able to be wired up without having to disconnect the Z limit switches.

As for the Err2, mine has now reliably gone away after noticing the connection for the wire going into the Hot 1 Interface on the motherboard wasn't tightened very well. Tightening it solved my issue. And yes, after Err2 is gone, the movement tool and all the menu options now work properly.

I think I'm all setup for my first test print, but unfortunately my computer doesn't have a micro SD card slot. Waiting on an external one to arrive so I can begin testing.