Okay, first things first:
If you haven't done so already, TALK TO YOUR ACADEMIC ADVISOR!! (I know that I (former advisor for the Geol. Dept. here) would be royally pissed if I knew that my students were going on the Internet for academic advice...). They will have more knowledge about the particulars of your situation then we do. Furthermore, talk to the paleontologist(s) on campus about their recommendations.
Okay, be that as it may, my advice (again, knowing nothing about how many other requirements you have yet to fulfill, whether you have to do a senior thesis, your grades, the quality and content of the particulars of the courses, etc...).
1) You are an undergraduate. Your task is to learn. The classes are more important while you can get them. Seek internships during summer.
P.S. Regardless of how many Biol. classes you get in these last few semesters, you will still have to pick some up in grad school, too. This is not a Bad Thing. Your task as a graduate student is ALSO to learn.
2) Tough call. This one will depend on several factors (not the least of which being how many other lab courses you will have to take with them). It is important to get the nuts and bolts that you learn in Vert. Zoology. On the other hand, as evolutionary biologists our first and foremost goal is the understanding of the history of life on Earth (aka evolution): other aspects (like the anatomical evidence of that history, the schemes of classification to talk about that history, etc.) are simply means to that end. My recommendation: if possible, take both of these and don't do anthro.
3) Double majoring is a good idea if and only if planned for early, at least by U Md. rules. You REALLY have to talk to an advisor in this case, to get the nitty-gritty of U Memphis rules. Unless they have very lax requirements, I don't see how you could complete a whole separate additional major in just two semesters.
Furthermore, you don't need to be a double major to be a paleontologist!! Most of us were just a single major as an undergrad.
4) An extra semester or two might not be a bad thing. However, this adds the additional aspect of the COST of an additional semester (or two). So in that case, you'll need to seek out not only the academic advice but the advice of your source of tuition payments (if that person is not yourself).
5) Any other advice... "The New Journals section of the library is Your Friend." "Ideas by merit, not by source." "When in doubt, punt." "Neither a borrow nor a lender be." Hopefully at least one of those will be useful someday.
Hope this helps.
P.S. See your advisor... :-)
Thomas R. Holtz,