Dawless to Cubase and back - setup adjustments suggestions?

My current “DAWless” setup mainly consists of a Digitakt, an OB-6 and a Yamaha MG10XU mixer. There is more but for the sake of simplicity let’s stick to these for now. Everything works fine, mixed stereo out to the monitors and all good. I now want to start recording my synths in Cubase (currently on 8.5). I’m trying to think of the best (simplest) way to do that while maintaining my current setup without having to change too many connections every time I need to use Cubase.

Just to give a bit more context, Digitakt’s Overbridge allows for multitrack recording via USB. OB-6 has USB as well (but other synths I might use in the near future might not have USB). The mixer I’m currently using does not allow multitrack recording.

Combining all the above, getting an audio interface would allow me to get audio from my synths via USB straight into my computer, or through the audio interface (e.g. for my non-Digitakt synths or where USB is not necessary). I would then get the audio interface’s out to the monitors.

The above would completely separate the Yamaha mixer in my current setup from the DAW. To record and playback through Cubase I would have to connect my synths to Cubase either via USB or through the audio interface but also output audio from the audio interface to my monitors (monitors can take 2 inputs so one would permanently be from the mixer while playing DAWless and the other one from Cubase when that’s needed).

Does the above make sense? If not, please don’t hesitate to provide additional setups.