For monitoring the source device (DAW1 in your case), you need the usual in-place multiple track or stem soloing, on a choice of speakers or headphones. There is no mix to monitor at this point.
Subsequent monitoring points are the stereo analogue mix and the captured mix (a DAC output pair from DAW2).
I have found that a push-button selection for the monitoring points using auto-release buttons is better than a rotary switch, as you can go rapidly between any pair of monitor points without the possible need to toggle through an intermediate one in the rotary switch case. I bought a simple multiple stereo loudspeaker selector, stripped out the wiring, and re-worked it to have combo XLR/TRS connectors and screened leads internally.
I think that using my patchbay to mult the Lynx to both the Folcrom and the ST will provide my DAW 1 feed to the ST for immediate button switching between ST feeds for comparison (Chris mentioned this in a latter post). That would add to my overall gain and leveling challenges but manageable I think.
To monitor the DAW 1 mix I would have to find a way in Nuendo to get a 2 bus mix out to the Lynx converter >patchbay. So far this takes a lot of "mousing around" with the sends and groups in Nuendo. So I may have to live with this and try to cut the moves down to as few as possible.
With judicious use of analog gear 2 channel outputs (all out to the patchbay for configuring to send to the ST first) I think I can route the analog chain to ST inputs relatively easily to at least one of the 3 possibly 4 inputs of the ST.
So that could leave me ST input 1 for DAW 1, St input 2 for analog gear and ST input 3 for DAW 2 capture mix at a minimum.
I apologize to the OP if I've strayed too far working through my situation out loud here. It helps me think this through with the hopes of criticism about my thinking and deficit of experience.
Thanks for responding Bos. I highly value your experience, expertise and willingness to share like so many others here at RO!