I have checked the C. Hummingbird. I don't think it is right though. The color is very dark and the lip has a lot of species characteristics. It also appears that the C. Dubiosa x C. walkeriana has not been registered yet? I also have checked the Lc. Hsinying Skies. The shape and color of this one is almost identical to BD's plant except the coloration of the lip which has more yellow/purple and the purple lipstick is larger. So I think that BD's catt is a Puppy Love cross with another catt which has strong walkeriana lineage. That is why the Lc. Ann Akagi is so close. Among 58-something registered Puppy Love crosses, I would eliminate anything registered after 1995. After that, I would eliminate all crosses in which the other parents does not have walkeriana in it. I think at that point, we probably don't have that many crosses to check. BTW, the reason I thought of the Puppy Love is because this plant is a very popular parent for the types of BD catt's blooms.
All of this checking and researching could be a fun project for a weekend!!!