Piecing together an A/C system

I'd go with the 134 for freon.
On the expansion valve setup most moparts used that setup, there were a few that didn't, but they are much newer. Cars like the 2010s avenger and I believe some of the 97-02 trucks used orifice tubes but we're "captured" meaning that to replace the tube, you had to replace the whole line. Stupid.
Many used a capillary tube within another tube (like a sheath mounted next to the actual ac line) for freeze up protection. I've seen that on F M J cars (diplomat etc) and some of the 80s trucks. The new lines I bought for my 85 D150 have provisions for it (aftermarket lines but factory configuration)
seeing how it's wired in, by the factory wiring diagram for my own truck, it's in series (think Christmas tree lights) with the "hot" wire to the ac clutch.