Most DSCR programs will want you to have owned the property for more than 6 months to allow you to use appraised value instead of cost.

Not much in terms of online reviews as far as I can tell

I'm on the hudvash program and have been on it successfully for 16 years.

There are 30 year fixed options and there are generally programs for 1-4 units and 5-8 units. 

Your interest rate, on a fixed rate loan, should remain unchanged and your mortgage should not be called due.However you should still confirm that this is the case with your lender (and read your mortgage commitment) out of an abundance of caution and because some loans and programs do require a longer seasoning period.

My original plan was to utilize a real estate agent to be my property manager that I met through a Dave Ramsey referral program, but I'm exploring if I should attempt this on my own.  

It seems there’s a common misconception largely influenced by social media, online courses, and influencers who oversimplify the process that real estate is an easy, passive way to generate income with minimal effort.

There are down payment programs for duplexes, i have not searched or tried to do a 3-4 unit property. 

Can't find much online....  

I'm starting a property management company and I'm curious to know how people have marketed themselves online.