Video update:

The GM compressor I bought had a bunch of wiring that I gutted. It had a 3 pin pressure sensor that I'm assuming goes to some control box that turns the pump on/off. I cut off the red/black wires directly to the compressor and crimped on a DT connector. Power goes to a key-on relay and ground goes through a generic 120psi pressure switch on the tank.
Most of the OE compressors have an integrated dryer. I left mine one and used a compression fitting to mate the OE flexible outlet tube to push lock. Works well, but I have a small leak from old OEM O-rings at the compressor-dryer. There are a TON of OE cars with air suspension now. You might get something nicer on eBay from German cars, but also potentially more complicated.

LT4 longblock (shortblock and LT4 heads) sold
10L90e sold

Remaining:
L8T shortblock fully built for 1500hp+ with ARP2000 head studs
LT1 heads resurfaced with BTR dual spring kit
L8T heads stock
LT2 intake manifold
LT1 hi pressure DI injectors and pump, LT1 throttlebody
new BTR225 cam, pushrods, head gaskets, stock bolts, tchain, VVT limiter
new Holley LT muscle car swap oil pan
valve covers, coil packs, rocker arms (LT1) 

I've been away for a while, and just took a closer look at the inputs you made to the suspension calculator in post #757.

In "Unsprung weights", you put 220 lb front, 230 lb rear. The calculator doesn't make this clear, but those inputs are supposed to be "unsprung weight per side in front" and "unsprung weight per side in rear". It looks like you put in total unsprung front and rear weights, so for example, the calculator is assuming your unsprung weight per front corner is 220 lb, not 110 lb like you mentioned your text description.

This is verified in the results. Look at the "Sprung weights" in the upper left corner of the results, and compare them to the total corner weights you entered. Basically, the calculator says you have a total of 900 lb of unsprung weight. Not even heavy-ass chrome wheels from the 1990's would make the unsprung weight THAT bad, ha!

Thanks for the clarification. I replugged everything in and updated the ride freq to 1.8/2.0 hz. It looks like 300/350 spring rates would work well.

The Mustang struts have been kicking my ass in the CAD model. They hit the control arm/ball joint unless I make tubular arms with a jog. Once that's solved, they hit the tie rod at full lock.
Moving the strut centerline further back on the knuckle now messes up the brake mounting bracket, so that's annoying.
I pulled the trigger on a pair of Gen6 ZL1 front struts. They look shorter than the Mustang struts, but the Rock Auto measurements have already lead me astray on the Mustang lengths.
I bought Chinese OE replacements off Ebay for $260 shipped for the pair. Mostly because it'll be easy to ship them back if they don't fit.
I'm also annoyed that I've already cut up one of the Ford OEM struts to mock up the coilover sleeves. It feels less bad to cut up cheap Chinese struts, at least.
If they ohm out the same as OEM (1.2ohm), It's worth a shot.
There are plenty of mostly-positive reviews for knockoff replacement Mag shocks out there. Mostly for GM SUVs, but hopefully these are decent.
BWI (Beijing West Industries) is the owner of the Magneride IP and manufacturing, so it's entirely possible these were made on 4th shift and left out the back door lol.
They're supposed to show up Wednesday, so I'll get them measured, scanned, and into CAD.

The Whiteline bar fits, but it has 10mm bolt holes, so looks like I will have to drill them out to fit the 7/16” end link bolts.