.), are there any particular upsides or downsides of purchasing all single bedroom units vs. a more traditional mix of units for a property that size? 

You mention a traditional STR PM agreement where the upside is shared by both parties.

Why not just buy the property with a traditional DSCR loan and avoid the complication?

My wife and I have been investing in real estate using creative strategies that don’t rely on traditional bank financing, and it’s completely changed how we look at deals.

So the money flows from my traditional IRA holder (like Vanguard or Fidelity), to DirectedIRA (my SDIRA custodian), to now Axos bank which is in the name of my LLC. 

Depending on how much you'll like to contribute to this retirement account keep in mind the self employment taxes you may need to pay of 15.3% and age if contributing to a traditional not roth type retirement account.I agree with the above based on your answer you most likely won't have issues in FL.

Traditional bank financing with a construction loan for repairs

This typically means lower down payments and better interest rates compared to traditional investment loans.

My first location I would go with a mix.  30 wide traditional drive up, parking and cargo containers.

Got an above listing offer in 4 days with someone who was able to get traditional financing through JP Morgan.