tried to use Edge for doing my admin work with Exchange 2013, worked fine up to some point. no amount of clicking would open additional dialog box or 3rd dialog box (most notably, when I want to "View Details" of a mailbox like to see the Exchange features it have).

The Edge server only participates in the routing of SMTP mail flow.  It doesn't have anything to do with ECP.  You shouldn't have clients pointing to it for anything.