(I've already begun work on spreadsheets, but finding out the specific fees and management rules for each condo/condotel is daunting and I don't want to start actually shopping until I know a lot more about each condo association).- I am totally aware of the problems with condos.

Each state has its own rules about what can and should be done with items left by a tenant.

I recommend you do go out and talk to at least three brokerages and ask them what support and training they will provide, commission breakdowns, and what costs are they going to charge (usually a desk fee)?

It is harder today to differentiate between companies and offerings than ever before, but that doesn't mean that running numbers on Turnkey properties is any different than other single-family homes.The 50% rule is a well-accepted, quick assumption calculation for determining net rental income on a single-family house.  

I know some of the keys have rules against anything less than a month though.

The property does not have to be occupied, but the lease does need to be executed.  25% equity is usually the sticking point for most with an FHA loanConventional loans will only require the executed lease to count the rental income of the property you are leaving.It might not even matter if you could afford both loans but if you need rental income the above is what you need to know.OVERLAYS - having said all of that, the bank could actually have rules that are different than what I described above. 

Also not sure if your condo has many requirements for tenant approval and abiding by rules for any short term rental so do you find it be relatively simple to handle from another state?

The one in the redfin link, show that:sold date:   3/30/2018sold price:  $290,000Total Rent (inside the listing details):  $3,250  ($900 + $850 + $750 + $750)For long term buy and hold, it meet the 1% rule requirement. 

Any advise on the rules/ requirements for Missouri would be helpful. 

I’m leaving my 9 - 5 to pursue this full time, and am ready to work a second job to support the transition (in addition to tapping the savings I have set aside for the career change).