Look up seller financing agreement and combine in with a purchase option agreement. 

Although the odds of something bad happening are slim.....stuff does happen.If you could find out who is in charge of this you could at least sign sort of agreement regarding liability....?

For many investors I just limit the agreement to homes I show or alert them to. 

Using your VA benefit is a great way to get started in real estate.When buying properties, lenders wanted to ensure the property we were leaving had a lease agreement or under a property management contract.Qualifying for a VA loan has slightly different criteria than a conventional loan.I wish you all the best in your investing journey.

Getting back to the original posters question an attorney should be drafting the operating agreement but its beneficial to have an accountant weigh in on tax matters.

There are different forms of buyer agency agreement , including a non exclusive agreement in which you can work with more than one agent at a time , this is probably best for the investor.

However kudos to you for taking the time to read and understand your loan agreement.

Quote from @Trey Fischer: BP has some type of collaborative agreement.

Buyers agents can't show a home without already having a buyer broker agency and commission agreement in place.

Get a written agreement from the neighbor that they'll allow it to stay but it must be moved onto your property if it is every replaced.Talk to the neighbor and see what you can work out.