Congratulations on your decision-- the next few years will be devoted to a lot of hard work but it will be worth it in the end. While I can't answer your specific questions about Baker or Mott I thought I'd tackle some of your more general questions until someone who can answer specifics gets here.
The reason why many schools have a wait list is because they are only able to admit far fewer students than who wish to attend. This is due to state mandated faculty to student ratios (8 students max per clinical section) and there is a shortage of qualified teachers at the moment. I think Mott's wait list is fairly long (I might have read 3 years on here somewhere) and unless I'm mistaken I don't think Baker has a wait list-- they are competitive and admit based on GPA among other factors. I would contact both schools and see what their policies are-- some require you to take a certain number of credits at the school to be eligible.
A nurses aid doesn't have a certificate and thus starts lower in pay.
A certified nurses assistant earns a certificate from a community college or other training institution and will start around 9-11 dollars an hour. You will be doing a lot of grunt work-- bedpans, bed baths, lifting etc. If you don't like throw up or other bodily fluids a whole lot this might get in the way. CNAs deal with all sorts of bodily fluids...
A licensed practical nurse earns a two year degree and passes the NCLEX PN at the end of the courses to obtain licensure as a practical nurse. New LPN grads in a hospital will start at about 14 bucks an hour. LPNs have many more duties than CNAs and a greater responsibility. Many LPNs work in long term care facilities as there are far fewer LPN positions than RN positions open in hospitals.
Registered nurses can either earn a two year degree from a community college or a four year degree from a university. Holders of these degrees sit for the same exam-- NCLEX RN-- upon graduation and have the same job of registered nurse. New RN grads in a hospital will start around 22 dollars an hour. A RN will have a lot more responsibility than all the other mentioned jobs.
Being a nurse requires a special type of person. I would first talk with many nurses and job shadow both a RN, LPN, and CNA if possible. That will give you an idea of what a day in the life of each is like. Also contact schools and see what their policies are. Then the fun of prerequisites and hopefully nursing school starts
Good luck to you!