In the list above, #3 does not seem possible with the current setup. Am I able to send audio from my synth to my DAW and Digitakt at the same time? Or at least have the cables connected and flip between sources?
I read that Digitakt can act as an audio interface, but wouldn’t I lose stereo audio from the synth because Digitakt is strictly mono?
Digitakt is stereo, it samples in Mono but it has a stereo input. You can have the incoming sounds just play and be effected by the Digitakts effects if you want. Once you start recording it sims the stereo to mono but until then, the audio input and pass through is stereo.
And yeah, that’s what I’d do in this case. Plug your Synth into the digitakt input and use the digitakt as an audio interface. You don’t even really need a MIDI cable between the two as you can use MIDI over usb and send midi to your synth that way, assuming you always have your DAW open when making music. But of course, you could use a MIDI-Din if you felt like it.
Or you could record the audio into Ableton and then use Elektron transfer to send the samples to Digitakt. But the audio interface seems entirely unnecessary if that’s all the gear you have.