Sorry, if this was more than you were asking but I have considered opening my own escrow company, I have been in core leadership at 2 separate ones and seen almost every scenario struggle.

Seasoning, an important question that must be considered, whatever the policy the individual lender may have, make sure you receive this in writing. 4.

Are any of the properties individually titled or is there one title covering all 4 buildings?  

As a FEW examples: how do you value the individual units so the other person can "buy out" the partner. 

Start attending some local meetups and networking with individuals in the city.  

Unless the properties are in close vicinity for easier management, I suspect they will sell individually.

There are a wealth of knowledgeable individuals on this site with many years of experience in building wealth through real estate investing who are happy to answer and help driven new guys discover the way.

However I do not work with individuals who use multiple agents.

They have way to many properties to deal with them on a individual "Special Case" basis.It doesn't matter if the current owner of the property has marketable title.

However, most of them (if not all) actually do not have a company and will do this as a non-license individual.