Next problems to solve:
1. Metric tubing ends - as long as I use the Camaro hoses and tubes, the only problem is joining the Malibu center hose (SAE) to the metric tube ends. The tube ends at the caliper hoses have a 'bubble' flare. Solution is probably going to be cutting the center flares off, swapping SAE nuts, and re-flaring the tube ends. Have to shorten anyway because the Malibu axle is narrower.
2. Tube/hose brackets - mounts to the lower control arm boxes - have to decide what mods to make and where to mount.
3. Parking brake cables - the lower control arm boxes on the Malibu are closer to the backing plates - there isn't enough room to slip them over the parking brake arms and flip them 180 degrees unless I take the backing plates off and install them first. Make replaing them later a headache, since I'd have to open the differential to take the axles out to get the plates off...
4. Caliper abutments - there is about 1/16" clearance from the outboard side and the outboard edge of the rotor face; there is about 1/4" clearance from the inboard side to the inboard face of the rotor. A little math suggests I split the difference and make 3/32" shims to put between the axle flange and backing plate, moving them outboard to match. That's between 12 and 13 sheetmetal gauges. 14 is more common (but thinner), so that's probably what I'll end up making them from.
Oh, and though I have to swap the left and right backing plates to mount the calipers on the rear of the axle so they don't hit the frame, the calipers themselves need to be in their OEM positions so the bleeders end up on top.
The last one is a material science problem - it's an interstitial defect in the chicken nugget lattice structure. Don't want to leave one nugget in the freezer bag.