(Him and his wife will have a renter's insurance- we are requiring a minimum coverage unto $100,000 but might need to up that if we allow a gas stove).

Florida also has a Windstorm Pool that provides coverage for Wind in certain areas. 

Insurance coverage, creating an LLC?

I'll keep the personal umbrella, and my agent said I can get a commercial umbrella policy to cover the rentals now (at ~$350 a year or something like that), but he also said it might not be necessary, since each property has coverage for $1 million per occurrence and $2 million per year.

If wind or flood damages the interior of your unit, you would have to have those particular coverages to be covered.

I've had some commercial lenders also look at my global debt service coverage ratio, but they don't reduce the income by 25% so my numbers are much better when a commercial underwriter is evaluating me than for a conventional loan.

Even if the property is worth $800,000, the bank will only allow you to cash out in accordance to their maximum LTV  and what their minimum Debt Coverage Ratio (DCR) is. 

The tenants rental property will cover all of their personal belongings and since you are using a PM company I would assume you will not be keeping any landscaping equipment, tools or possessions at the premises to need that much coverage.

I am looking for home insurance companies that have great coverage and options for protecting pretty much everything under the sun.

I found reasonably priced and good coverage from Allstate.