Hi - I’ve got a UR28M which uses “Basic FX Suite”, which in turn appears as a product listed on the right hand side of my eLicenser window. After I update to C12 Pro, will I still need the dongle plugged in to use “Basic FX Suite”? Thanks in advance!

Most probably you will still need the dongle, as the Basic FX Collection is part of your interface, and not of Cubase itself. There should be an update in the future though, without need of the dongle.