I'm really curious how well the headset/stem system on the Downtube will tolerate that kind of repeated torque. The forces you're applying are much more horizontal than vertical, which is a different than a normal bike headset is taking when someone is out of the seat and wrestling.

For pedalling in circles: I don't see how the lifting is different than on a roadbike, other than you're not lifting your leg to do it (you're more moving it laterally upward).

On the recumbent I just got, I never ever need to apply pressure to the handlebar. I baby my hands over it like feathering them on a road bike during a climb.

The setup looks cool, and definitely more portable than most other SWB recumbent designs that seem to have at least a single long boom piece that measures ~45".