I am a Columbus based musician looking to supplement my inconsistent income with some cash flowing rental properties. 

If it is cash flowing negatively already, you are already supplementing it now with your regular income.

I am still active duty military and investing heavily on my time off in an attempt for my passive real estate income to supplement my military income at retirement.  

The guys who want to retire; they aren't in a hurry to sell/not desperate, but like not having to pay a Realtor, AND they are interested in seller financing to supplement their income.

Budget for all of the direct and indirect expenses.Be comfortable hiring others to supplement what you do.  

My wife and I are discussing buying our first rental property with the aspirations of having 3 or 4 to supplement our current income and hopefully fund college for our children which are still young.Our plan was to buy a home at 50-75k and rehab it with 20-25k and then rent it for 1-1.2k.

At the moment I'm looking to supplement my income.

Meanwhile the other tenants will be helping pay your loan (ideally partially supplementing the cost on your unit).  

Passive income stream to supplement current retirement income.2.

I am a teacher and have two fellow educators who plan to working together to flip a house this summer to supplement our income in the short term with long plans of getting out of education sooner than later.