My goal is to focus on purchasing small multi-families to self manage with a STR/ MTR hybrid model in the Central FL market.

This could play a role in which unit you decide to occupy. good luck 

Investing in this deal appealed to me due to its stable demand, lower management costs, diverse tenant base, scalability, resilience during economic cycles, and potential for generating passive income.

Is this in conflict with the turnkey provider’s role as a property manager?

Here you will meet wholesalers who provide deals and all the cash buyers (rehabbers) you will need.To find out about an area go to IREM.org search for ARM certified property managers.

They dont teach basic fiscal management in school .

And in order to max out your profit you will need to self manage.

Also, if it is legal in your state/county, you need to ask for a higher deposit just to protect yourself in case, he decides to break the lease early a second time.Would I let him back in? 

Vacancy can vary, but if you work with a good property manager, you shouldn't have your property vacant longer than 60 days out of the year. 

For all of our clients we have everything from contractors, maintenance, lenders, property managers, and inspectors we recommend and work with everyday that can help get the information you need to make an informed decision before buying a property and help manage the property.