At the end of the day, cash flow was similar because I now had mortgage payments. 

The existing owner has it in a trust but it is not his primary residence. 

Quote from @Nicholas Dillon: I read somewhere that you can request to have your mortgage insurance dropped once your Loan to Value reaches 80%.

It also includes managing your existing investment well to ensure you aren't bleeding money due to bad tenants, excess maintenance, etc. 

Long term hold, with buyer planning on carrying existing financing to term without the ability to quickly cure default — terrible strategy with huge risk for both parties.   

Currently, I have about $20K left on mortgage and estimate value is$175K.

My question is, do I just not touch the first property, use the cash flow to reinvest and pay down the mortgage or save up for a downpayment down the road OR do I pull cash out of the first property to buy the next property?

I just completed my 20 hour course for my Illinois Mortgage Lending License and the final step is taking the state exam.

Could/would Mom be willing to add you to title and you both sign for a mortgage, once renovations complete?

Many likely have coverage for their mortgage balance or from many years ago.