That sounds like it would fit the bill, but I would expect to have to close them up every night until June so I'd probably hinge a front panel on.
My back is getting bad, so I'd have to build them at a comfortable working height, which will also help keep them from being too damp or too cold from the ground and would allow me to build storage cabinets underneath. I'd love to keep them along the wall just outside my office, by the egg fridge, to get word out that I have chicks available. Then I could also check on them frequently and they'd be at less risk from predators.
I'd do the tube feeders and nipple waterers for sure in a setup like that. They'll already be started on food and water so it ought to be easier.
I could even build a polyethylene and 2 x 2 greenhouse style frame to box in a corner of the covered porch. Up against a west and north wall of the house, with sheltered southern and eastern exposure, that would probably work well. And I could put my cool weather crop flats out there too!
For heat I'll probably use FlexWatt all along the back wall. It seems it would be the easiest solution. I'll have to test it to see if it provides enough heat.