I have been researching ways agents generate leads and I see that it looks like zillow and Facebook/google ads are pretty common ways.

The most common is a 5yr fixed rate period. 

It is common to ask for tax returns for commercial tenants.

I hope this isn't a common thing (once per month or less).

If you are worried your tenants lack common sense, remove said plants.

@Lucien Gautreau 1% earnest money is common in commercial, so 10k EM on a 300k purchase price is high.

At any rate, this is definitely legitimate and very common.  

Miami, Orlando, Tampa, Jacksonville are all different markets, but then you have the Panhandle markets like Pensacola, the really posh and high-end area of Naples, and the Northern part of the state that has more in common with GA than it does Miami.

Having worked from home for a long time I know the climate has changed and working from home is more common/acceptable.

Some of the more common contingencies include: financing, appraisal, title, and inspection.