If you want to connect a MacBook to a DSJ via USB you might find, as some of us have already found and reported here, that the two devices can stop talking to each other requiring a reboot of the DSJ. So if that behavior still fits within your definition of “working” then yes, what you propose will work. If you use the DSJ as a pre-amp make sure your levels are tweaked so that 80 on the dial of DSJ doesn’t play too loud.
And about MQA unfolding and what happens where, just don’t think about that too much. DSJ is a Roon supported device. Roon is a supported Tidal device, but according to Tidal, DSJ is not.