How is this split between Math versus English/Reading?
I agree with others that you should not apply ED anywhere. Finances are more important than whether you end up at U.Maine, Williams, or MIT or somewhere else. One issue is that you will find other very strong students and good research opportunities at any of these schools. MIT might have more opportunities, but competition will be intense. The academics at MIT are also quite intense even if you do not have a financial need to also hold a part time job (although some students do manage to do both). At U.Maine while you will find other very strong students, you might be able to at least be a bit closer to the top of the class, and thereby stand out a bit and get to know your professors, and still find good research opportunities.
PhD’s are usually fully funded. However, the funding is sort of minimal, or perhaps covers tuition and fees and a small stipend (and health insurance in at least some cases, including our daughter’s current PhD program), but the stipend is typically barely enough to live on. Paying off student loans at the same time could be tough. A master’s degree is usually not funded. Minimizing the amount of debt that you take on for your bachelor’s degree will be valuable and could open up some opportunities down the road.
Research experience is likely to be at least as important as the difference between any two schools on your list. This position sounds likely to be valuable, without my knowing quite what it consists of. This can both help with a first job after graduating, and also help with graduate school admissions.
I think that you are doing very well. MIT (and Harvard and Cornell) will still be there when you are applying to graduate programs.