Honestly, I would really hold off on law school at this point. You need to do more research on what kinds of internal promotions or job changes a law degree, and specifically a law degree from those schools will afford you. You need to get out there and talk to several people who are in the jobs you want to have when you finish the JD. Your plan simply might not be feasible or the JD may be entirely useless or unnecessary to accomplish your goals. If you have no contacts, you can start by cold-calling / emailing these people and ask if they'd agree to do a 20 minute information interview about the work they do. You can pick up some books at the library that explain how to do this.
For example, I knew a guy who was in his 50s and had worked for a state university as a tenured prof for a number of years. They promoted him to an administrative role within his department. His job was pretty demanding. He decided to go to law school at night(at a school that had a decent rep in the area, but no national rep) because he thought getting the law degree might make him a more competitive candidate for higher level administrative jobs at the top universities in his field. Turns out he was wrong. Those universities didn't care one iota about whether or not he had a law degree and were much more interested in his work experience. He eventually quit law school during his second year, I believe.
If it turns out law school really is the right decision for you after you've thorough research, you can go next year or the year after or whenever you feel like it. There shouldn't be any reason to rush into law school, especially if you are going PT.
Anyway, most schools do not offer generous scholarships to PT students. Where do you currently have residency, by the way? Why are those the only 3 schools that will work for you? GW, Gtown, GMU, and American also have part-time law school programs in the area. Not saying that any of those schools would change anything about what I said in the first paragraph, just curious as to why those 3 schools you mentioned are the only ones that you say will work for you.
As far as the bar goes, neither school will necessarily prepare you for the bar. Law school doesn't really prepare you for bar per se. That's why bar review courses like Bar/Bri and the like exist. You won't pass the bar without one. Some schools focus their curriculum on courses that will be tested on the bar and tailor exams to help students get in the basic mindset of how the bar works. That's why certain lower ranked schools have very high or very solid bar passage rates.
UDCs bar passage rates have historically been atrocious. They are getting better, but they are still below the state averages. My guess is that a lot of UDC students do not prep adequately for the bar, or the school still hasn't done enough to focus the curriculum on bar courses and bar focused exams.
Compare to UBalt, which is not amazing but very close to the state average:http://officialguide.lsac.org/SearchResults/SchoolPage_PDFs/ABA_LawSchoolData/ABA5810.pdf
Part of the reason UDC's reputation amongst the legal community is so weak probably has a lot to do with their historical bar passage rates. I believe at one point less than half of their graduating class was able to pass the bar. Not only that, but the region you're talking about is a very elitist place and UDC has a very poor rep as a university in general. UBalt is not a heavy hitter by any means, but it's somewhat respectable, and has a solid rep in MD. Like I said, UDC is seen as bottom of the barrel throughout the area. Even if you pass the bar on the first try, you may find it impossible to find a lawyer job when your pass results come in because the rep of the school really is that bad.