I don't really think you would need to specifically know that BF3 is sp2 hybrized and has an empty P orbital for the MCAT. This information is a little too detailed.
Just know in general what hybridization and orbitals actually are.
As far as being a Lewis acid, if you're looking at a drawing or Lewis dot structure, you'll be able to tell that the compound BF3 doesn't have a lone pair. The 3 bonds with fluorine account for 6 electrons total, and thus it needs an additional electron pair in order to complete its octet.
Lewis acid = electron pair acceptor. Lewis base = electron pair donor. I remember these by just thinking of them as exactly opposite of Bronsted-Lowry acids and bases, the Bronsted acids being proton donors and Bronsted bases being proton acceptors, respectively. Protons and electrons have opposite charges, and acceptor/donor mean the opposite thing.