Without an income stream your not going to be able to obtain capital or loans.

Disadvantages - more risk only one income stream when you go vacant, cap ex cost more because it’s not shared by two or more income streams, generally lower cash flow than a multi family. 

I do by and holds but do that outside of my 401k and live off of the income streams.

In MY mind a payment stream for 5-30 years to your heirs would be a nice legacy to leave, but we are all different. 

The nephew (sole blood relative) has never lived in the house.

I'm an active healthcare provider, but looking to develop a reliable stream of passive income over the next 10 years.

Income streams!

Inexperienced or conservative investors do not grasp the concept that every property has two distinctly different income streams.

Typically landlords would describe emergency repair requests along the line of involving "fire, flood or blood" (if this helps).One would assume that a tenant with a lousy credit score, two pitbulls and a yearly income that places her on poverty status would be grateful any landlord would rent to her. 

I am looking to start investing in real estate to supplement my income, pay off my student loans, and eventually develop a substantial "passive" income stream.