I’ll let others give their take as well, but when I entered the BA/MD program, if you were OOS, you agreed to pay OOS tuition for the full-time you were in the program. In fact, before matriculating you were actually made to sign an agreement stating exactly that: “Out-of-state residents applying to this program agree to the non-resident fee payment and other fees paid by resident students for a full six years or longer if individual circumstances require and agree not to apply for or otherwise claim entitlement to any UMKC non-resident scholarship.”
That being said, I believe this may no longer be true, as I have heard of students who buy some type of property (a condo or a house) to try to establish Missouri residency, some of whom have been successful. It’s a whole petitioning process as you probably already figured out from the website: http://www.umkc.edu/residency/. And you’re in no way assured of having it approved. What trips up people the most in terms of approval is usually the Missouri income tax liability requirement of at least $2,000 in income. Rules can be loosened or tightened up all the time at the state level which is why depending on the requirements students may or may not have been approved even if they all did the same thing to check off the boxes.
You can go here thru Mizzou (the same rules will apply since it’s all in the same UM system) since it’s easier to read, as that UMKC residency petition looks a little blurry: http://registrar.missouri.edu/residency/. They also have a helpful Youtube video to explain what you need. Best would be after you get an acceptance to the program, to ask around and to get in contact with an out-of-state BA/MD student (best would be from your state) who can tell you about how successful people are in being able to do so and maybe get you in contact with someone who did.
Great question though, and hopefully others here can shed some light as to how it is accomplished by students currently.