Or if Possibly attaining a Brokers' license (my career is in a different field)?

If you can get a 20 year a 10 year period may be attainable. 

Do you have a target profit you want to attain?

if your son is also the natural child of your SO then he may have power over your son's assets but you could try naming a guardian in your documents to try to get court oversight in the event you die before your son attains the age of 18. 

My purpose is to attain rental income through buy and hold, but I left it out of this question just for simplicity of understanding the mortgage component. 

My main goal is to attain financial freedom through real estate.

The ONLY place that I can say the 1% rule on a turn key investment in the DFW area is attainable is in a new development (new construction homes) being built in the cities of Forney & Heartland TX. 30-40 mins away from Downtown Dallas.

There is no minimum number of units to attain the real estate professional status.

As Amber mentioned you will have a lot more liquidity on a duplex or single family than you will have on a property with more units.I also agree with the comments that that level of cash flow would be hard to attain in the current market without a decent cash down payment or unless you purchase a property with 4 or more units and 25% down. 

Most income properties trade between a 5-7 cap, with the 1% rule still attainable with good research and negotiating skills.