I have not put the research into boas that would be necessary to give you an adequate answer, but I believe het coral albinos do exist. in fact I purchased one. it's my only boa, and I don't have any breeding plans, at least for quite some time, but I am curious to know what you find out.
analgous to the ball python albino vs. lavender morphs (which are incompatible), I had thought that there simply several discrete albino strains, coral albino being one of them, but perhaps that was erroneous. if it takes a motley + albino to create a coral albino, I'm more ill-informed than I thought I was.
edit: below is a section on coral albinos from Peter Kahl's website. it would appear that I was generally correct.
''The coral albino boas originated from one of my original hetero bloodlines I produced in 1990 or 1991. When I bred hetero's from this bloodline I noticed several of the babies were much more colorful and had a lavender coral color to them. I kept them back and as they grew there color intensified to almost a coral/lavender body color all over the animal.
In summary, the coral-albino trait produces extra amounts of red and orange pigmentation that shows up along the flanks, saddles and in the red tail patterns. At the same time, most coral-albinos exhibit attractive pink heads and flecks all over the non red areas of the body as well. Like most line bred traits, not all coral-albinos, even in the same litter, will exhibit the same intensity of the coral trait.''