One would've netted us ~$15k, another only ~$1k, and the third is the triplex currently being renovated. 

Local laws may also include protections based on other factors such as source of income or eviction history.Disclosure Requirements: If you are using third-party screening services like SmartMove or another credit reporting agency, you must provide the applicant with an "adverse action" notice if you deny them based on the results.

A third friend of mine was looking on the web and saw some "deals" in Cape Coral. 

Depends on the contract language, but under typical language the seller is obligated to the sale if all contract terms have been met, and the jilted buyer can usually get a legal block prohibiting the sale to another party.

This is tough because of all the parties it involves.

LCC as a basic pass through and limited partnerships depending on equity arrangements and profit share of the parties add that extra level of flexibility and not needing to split potential individual partner costs or liabilities.  

When things go south, you'll lose the business and the relationship.If you decide to move forward, I recommend you talk to an attorney and develop a strong partnership agreement that protects all parties, gives everyone a way to exit, etc.

Funny enough, I ended up renting the property to 2 different parties this summer, both of which commented that it was exceptional value for the price point.

@Abigail Lipson if you move forward, be sure to execute a Partnership Agreement spelling out how does what, penalties for not doing those things and what happens when one party wants out (or dies/incapacitated) and the other doesn't.

I can see that third bullet point affecting arbitragers for sure.