Like most have said, corn snake morphs are almost always recessive. Tessera and aztec are a couple that come to mind that are dominant traits. I don't think there's any co-doms like in the ball pythons. Stripe/Motley are on the same loci, so you can breed a motley to a stripe and get hets or get a motley/stripe which usually has a clear belly with motley saddles that sometimes connect in spots to make a broken stripe.
I think the sunkissed is a selectively bred amel, if I'm not mistaken.
Good job on your pick ups! I'm working with a snow motley and some hypo lavenders. I've also got an anery, normal, and a bloodred corn. My breeding goal is a hypo lavender bloodred! We'll see if I can get that!