This, combined with you having a key to the property should be sufficient to address concerns that potential renters may have. 

The shed already has a silver liner type material and he says that is sufficient.  

I hope you have sufficient capital for the maintenance issues they tend to have.For such an apparently large firm, it seem strange that you seek advice on how to operate a property from an online forum. 

Keep in mind, for FHA, 3-4 unit homes must pass the FHA self sufficiency test.

We have some friends who work for a large hedge fund that has been buying up significant quantities of distressed RE all over the country for the past sseveral years and they have done quite well.

A simple email stating you have decided to use another contractor is sufficient. 

New listings of single-family rentals rose 18.4 percent in June, providing a sufficient supply of homes to meet the steady demand.

We dont see your file so everything would be hypothetical at this point but you might encounter FHA SS rule (self sufficiency rule) if you're trying to do a 203k FHA loan on a 3-4 unit property so make sure you know all of these rules because they can be deal breakers depending on your specific property or income characteristics.

I'm having trouble finding any single family homes that cash flow sufficiently in the Kissimmee/Davenport FL areas just by using the basic monthly expenses. 

So, conservative CPAs are not uncommon.Simply identifying three replacement properties within the 45-day identification period is not sufficient.