Brown website says it costs $80k a year. With all your “maybes” with financials, Im guessing it would still put you at about 40-50k a year for you to pay. Thats 160-200k in debt for your bachelors alone.
Sadly, your chance at a full ride at an Ivy League school is basically 0%. And while the prestige of their child attending an Ivy may sway the away from them wanting you to go to the free UF option, your chances of getting into an Ivy AND the cost being less than 20k a year is about 1%.