I have a step through model of that in green. It had the plastic downtube levers and one lever was broken. I used an orphan 10 speed thumb shifter for the left side and a spare S/A trigger for the right. The broken lever went to a member over at BikeForums.
^^^^^ What @SirMike said about adding a rear brake, and I will second the suggestion to replace the handlebars. I have a brake caliper and lever (both steel) that are yours for the cost of postage. I may even have an appropriate handlebar.
Edit: I just noticed that the caliper has a long...
The only bike of any interest is the chrome Mixte, but a buyer would be upside down by the time he got it in decent shape. The Phoenix should go back to ashes, and the rest I would sell for best (or any) offer on CL.
It seems to be very short for a tandem, and I hope that the stoker's handle bars are wide enough for the captain's butt.
Edit: It looks as if most of the weight is shifted to the rear - the stoker is hanging behind the rear hub.
You have contacted the right place for those bikes. I don't know about the value, but I would guess that the small, incomplete bike has parts value and the other has value as a nearly complete bike. Do they both have 24" wheels?
Edit: It appears that the boy's bike has a bent fork - but that...