Thank you so much for the pointers and the link. Much appreciated.
Your point about the spray finish is particularly well taken. Here's the sealer I used. It's supposed to be matte, but was much more glossy than I would have liked. Are there any better ones that you could recommend?
My next project has a lot of blue to their uniform again. I'm thinking I'll try to prime the whole figure in the Zenithal method the way I did with this one's cape and see how that looks.
I don't know about cracking, but I recently sealed a soft rubber cape with an acrylic sealer. I had stripped, primed, and repainted the cape already and it was fully cured and dry to the touch. I did two thin layers with the acrylic sealer and 48 hours later the cape was still very sticky all over. Five days later than that, it was no less sticky. I had to strip the thing and start all over.
Maybe you're dealing with different materials than me, though. Here's the sealer I used, and this is the action figure the cape came from. Didn't have any stickiness issues at all when I used the exact same processes for the hard plastic pieces.
Hope this helps. Good luck!