He would split the profits. the area Is consIdered hIgh end and partIcularly hot neighborhood.

My wants are a 10-15 door unit in the 750-900k price range but would consider something larger if it was a good opportunity.

Its a good deal for us either way, but of course, want a higher profit margin.  

He had not been successful at selling yet because it was not profitable at that time.

This is a larger city though and that may not be an option in smaller communities with a less diverse tenant pool. 

The basic reason you would want to keep getting more properties is because the return in real estate is higher than the cost of borrowing, so you want to borrow as much money as you possibly can and make it all generate profit for you. 

In short, my long-term plan is to begin investing in SFH (much lower barriers to entry) or small MFH (Duplex, TriPlex, Etc) to raise capital and build my resume with the goal in mind of getting into larger MFH/Commercial properties as quickly as I can. 

My wants are a 10-15 door unit in the 750-900k price range but would consider something larger if it was a good opportunity.

Closing costs don't always go to the lender - often they are 3rd party fees or fees that are not "profit" to the lender.As many other people said, usually the closing costs are financed unless there just isn't enough equity to make the numbers work. 

The properties I'm looking at rent for about $1000, so there is profit there, but then I need to account for management fees, vacancies, and repairs.