That is super cool!

The fenders i suspect are HD and not RD?

Those extra long tandem Cyclo derailleur cables are quite hard to find.
So my advice would be to be careful with that cable until you have a spare one.

It looks like it has a standard non flashy Cyclo derailleur braze-on and a brazed-on rear rack.
Maybe early 1940s - late 1930s?

Seems to have JEAY brakes, does it have a drum brake on the back? If so it might be a steel MAXI.

I'm not 100% but it looks like it has a Specialites TA adapter on the front crank.

It's good that it still has the ring on the front wheel for the speedometer.

It's a really cool tandem and i would love one like that at some point.
But you have to leave the motor on and try it with it!