He came to me to see if   I would be open to co-owning the property.

She was incredibly grateful for the help we provided and couldn’t believe her dream of moving to live with her daughter had finally come true.

When I did underwriting, since a portion of the insurance costs and property taxes are collected at closing, I reduced those from the first year of expenses.

Essentially how do we separate from partnering on each property when the time comes? 

I am willing to offer 5% ownership of any properties I purchase with them as co-signers.

Ordering an appraisal for such a small property would be silly. 

It was a self-storage property in a small town in Central Illinois with a recently underway residential development adjacent to the property, so lot's of upside.

BS, those same deals stayed on your marketplace for months after you said they were taken down, and they were not even available anymore (a "principal wholesaler" in your marketplace even told me one of the properties was no longer available, and your team was CC'd on that email!)

There are different types of investments like residential properties, commercial real estate, or short-term rentals.

Well we'd need a lot more details on the property before anyone can help.