This has been my strategy so far and just looking for some constructive criticism.

I think the most critical piece is preparing an accurate estimate.

I use a term I learned from a financial advisor from years ago: "Reaching Critical Mass".

It's critical that you immerse yourself with someone who has been down this road before. 

They should also be working on getting critical tax documents out for tax time before they are needed.Any sophisticated investor will look at the property, the sponsors and the financing to determine if it meets their risk level.

Another critical factor in these back-to-back closing deals is choice of title company (i.e., smaller is generally better!).

This is critical, because you would have to qualify for both your current house payment and the 4-plex payment based on your current pay."

Local knowledge is critical.

Learning as much as you can about the area you are planning to invest in is critical, paying special attention to industry that draws and keeps people in that area.

Before you stage,call a local real estate agent and ask them to come over to see the property and give you an honest critical opinion as to the way the house is showing.Tell them you are not hiring them to sell it and just want an honest opinion.They are going to want some money for their time so offer a hundred bucks or so.They hopefully will show you why it is not getting offers like poor decoration choices(too cheap or ugly),Poor curb appeal(bad choice of paint and landscaping)or the neighborhood itself is worse then you think.Bathrooms,bedrooms,and kitchen may not be big enough for most buyers as well.