If the place is in decent shape I would offer to credit it toward the next month's rent and write addendum including no future pets.

Sounds like a good plan, should have plenty of options available.I would be cognizant of any group you talk with on two areas, the location of the property including any potential concerns of it being 'rural', as well as the minimum purchase price and/or minimum loan amounts.

Make sure to include proper disclaimers. 

Here's an article with FAQs including the cost of a study.

LLC's separate your personal assets from your investments and offer you protection from lawsuits related to your property, they can help to establish a more professional image if you plan to expand, and they provide some flexibility on how you are taxed.There are some drawbacks, included fees and administrative work, but it's ultimately best to consider speaking with a CPA to determine the best option for you. 

No attempts to "pull one over" on anyone here--in fact this deal and partnership idea were brought to me by the other would-be investors (including the deal finder), because they're interested in making it possible for my wife and I to move closer to them (currently living in different states).

Yes, this means making an investment in a CRM that may include tools for direct mail, email, and text messaging... 

The plan includes high-yield activities such as property flips and strategic acquisitions to provide liquidity and generate returns.

After discussing their goals, we realized they would like to maximize the property's value while also including me in the process, given my background in general contracting.

Your calculations should include utililies and repairs, legals, snow removal, etc.