That sounds fine to me Julian. Vert structure is a very time consuming class, but you will definitely be happy you took it once you get into med school. It is taught and tested very similarly to how med school is taught (if Krukowski is still teaching it, but even if she's not, I'm sure it's still a good class). Believe it or not, most of the names and locations of stuff in a cat are the same in a human so memorize the names and locations well and remember them for med school. Definitely try to finish your distribution credits so that you can have some fun your senior year and take whatever you feel like taking. I finished my requirments for my bio major and distribution credits and just took some more bio classes that I thought would be useful for med school. The classes that I have found useful (or heard are useful) for med school are (in descending order of usefulness):
biochem, vert structure, cell bio, immunology, neuroscience, abnormal psych (take this class during the sememster that they have actors come in and act stuff out, you will have to ask around to see which prof does that), endocrinology, psych 100 (there is some behavioral science stuff in med school). Another good, easy non-medical class at Wash U is Personal Finance, the prof was really good while I was there.