Getting into medical school nowadays is no easy feat. The number of applicants has doubled over the past 2 decades, while the # of seats has not kept pace. Many students spend 4 years getting a degree +1 or 2 gap years. The main factors in acceptance is: GPA + MCAT. You’ll need a 3.8 GPA and MCAT > 514 to be competitive.
Med schools like to accept students with a wide variety of interests and backgrounds. Its not as holistic as applying to college, but keep in mind that having some interesting activities will make your application stand out. You don’t necessarily need to have your major lined up with your future post-residency goals. But having research experience will help (esp peer reviewed publications).
Neuroscience is a pretty wide field. Research in neuroscience involves specialized techniques such as cell biology, genetics, neuroimaging, and pharmacology. There are many majors that can prepare you well for a future career in neuroscience/psychiatry.
I really like your idea to focus on smaller LACs where you can get merit money. Graduating at the top of your class will be important. As well as keeping your costs down. Med school is expensive. You should checkout the SDN forums for more advice. Good luck