Thanks! I had trouble finding exact answers before, but now that I have a little more clarity about the Digitone-as-audio-interface situation, I think I have a better idea of what to look for, so I’m sure I’ll have more luck now.
Maybe I’ll check out if anyone has done a video showing Overbridge on Windows and describing their setup (I’m sure there are multiple).
Thanks again 
EDIT:
An update for people who might come across this thread later ~
While I still do not have a Digitone (not sure when this will happen haha), and so I have not tested it, I watched some videos and looked at some threads (like this one and this one), and it seems that, yes, you can concurrently use the Overbridge plugin, streaming Audio and MIDI from the Digitone (and 'takt) via the plugin, and a normal audio interface with ASIO drivers on Windows, and it should work pretty smoothly, especially if you follow the startup tips Elektron recommends and also match the buffer size in Overbridge to the buffer size of your audio interface. There seems to be no need for ASIO4ALL tricks or anything like that Windows users would normally need to use to get functionality like Mac’s aggregate device options.
That said, I definitely see a lot of threads mentioning problems with older audio interfaces / soundcards that are fixed by upgrading to newer gear (e.g. here) and issues with MOTU audio interfaces (which is also mentioned in the Overbridge FAQ), so if you have an older interface or a MOTU, maybe try to confirm that there is no conflict with your specific interface.