You're search area eliminates virtually every good bus. Fla. is notorious for low spec buses that get used up by cannabalizing other buses until they are worthless.
Auction sites like Govdeals.com, purplewave.com, publicsurplus.com are a few of the places that schools use for liquidating the buses. The dealers get the same buses we can and then double the price. No licenses are required for bidding on any of these sites.
What you'll find on FB and CL are people who bought at auction and then double the price to flip them on FB and CL.
The auction sites mentioned will know nothing about the bus, it isn't sold at the auction site. The bus will still be at the school and any info will come from the school system selling the bus.