Stealth matters only inasmuch as it ensures platform survivability, and the airborne missile carrier has the advantage (in this respect) that it can hide in places where the Soviets can't practically strike at it, like over the Great Plains or central Canada and then fire off long-range missiles at the enemy (say, the Minuteman...) without them being able to do anything about it. At least in theory.
I don't think any of the nuclear stuff is actually that interesting to talk about, though. It's all permutations of stuff that isn't actually going to be used and probably won't matter that much to stuff that will be used. The interesting kind of "Project Cancelled" material for the U.S. military is equipment that might actually have seen combat use, like the AH-56 or some such.
EDIT: In this respect, I think the '60s-era drone projects that the Air Force had are a very interesting possible area of AH. The Ryan Model 147 was a very interesting project that was like a '60s-era Predator/Reaper--they were even developed a version, the BGM-34, that was designed to deploy munitions, including precision-guided munitions (Mavericks, not Hellfires, of course), and had "stealth" versions. Similarly, the QH-50 DASH was a very interesting anti-submarine helicopter drone that worked fairly well in practice, given its design limitations. But in both cases the military dropped them in the late '60s and early to mid-'70s and pretty much forgot about drones for a decade and a half.
Now, these weren't exactly "project cancelled," since both did see service, but there was scope to make them much more broadly used and really the basis of a major integration of drones into the military much earlier than occurred IOTL.