I rent at MCO several times per year, and I am 90% confident you won't get offered a Tesla. The AVIS MCO location only has a handful of Model 3s and no model Ys. Given you've already booked an SUV, odds are they will offer you a Ford Edge, Hyundai Santa Fe, or hopefully not the lemon Acura RDX I got last week.

I'd be more concerned if you were renting from Hertz next door. They have an entire aisle full of Tesla 3s and Polestars.