Looks like it needs flooring, paint, countertops, cabinet refinishing (or replacement), roof repair, dry rot repair, maybe foundation repair, lots of wall repair, and possibly plumbing/electrical repair (nothing can be seen in the photos but common in that area).I agree with @Dylan Vargas that there is no money to be made in flipping this property based on your numbers. 

Roof, kitchen, flooring, trees etc. 

It's definitely doable and only needs some minor repairs and cleaning/painting. 

Like above screen tenants and screen heavy, set expectations quickly and clean on communication and anything within the lease agreements.Location of course, pick somewhere business wise of potential growth/sustainable economics so when you move out you can easily lease out not only your unit but the other during turnover.

As an out-of-state investor (Live in PA and have property in DE), we do our own property management (Short-term Vacation Rental Condo) - HOA does all the outside and pool stuff and we book, stock, and clean it ourselves...so I can't help you there either.   

but already there's a curve ball thrown at me...The occupancy inspector office will require that we add a full staircase, either wooden or metal, from the 3rd floor of a brick 3-unit in south STL.  

but already there's a curve ball thrown at me...The occupancy inspector office will require that we add a full staircase, either wooden or metal, from the 3rd floor of a brick 3-unit where I'm buying in St Louis.

It has a studio apartment on the ground floor that i keep for my personal use.

You can see pictures of  previous projects by searching "google business marx-on-your-floors" and more by before/after pictures by searching "marx home repair Facebook ".

If it’s a higher-class neighborhood, maybe stainless steel appliances, but they do need more cleaning.