After hearing about, and personally encountering some horror stories of disagreements between homeowners and contractors, I am wanting to establish a clear contract to use with a new general contractor. 

I'm assuming you're referring to investors that provide all of the funds for your flips? 

Get at least 3-5 quotes and check references.

Then I consider letters of reference, cosigners, and added security deposit in order to meet approval. 

When I'm figuring out how to price an Airbnb I always cross-reference AirDNA or PriceLabs to get an estimate on what the income would be.

Your value is, to provide sellers that don't want to list, with a way to get cash for their house and provide buyers with discounted off-market properties they can buy to make a profit on.I am not saying it is not possible to wholesale from the MLS, but it seriously defeats the purpose.Focus on becoming the person/company that offers the most and best value and you will succeed.

We do not charge a fee to our members and we do receive a broker to broker fee, but it is up to the broker to pay the referring broker, and GEG opted not to pay us. 

My intention is not to discourage anyone from investing in the Costa del Sol, especially considering that I never specifically referred to this region.

It's possible the laws have recently changed so reference the Florida landlord/tenant handbook.

Avoiding the occupants from squatting is best addressed with background checks, employment verifications, and references before signing the lease.