Title VICIVIL PRACTICE AND PROCEDURE Chapter 83 LANDLORD AND TENANT View Entire Chapter 83.49 Deposit money or advance rent; duty of landlord and tenant.—(1) Whenever money is deposited or advanced by a tenant on a rental agreement as security for performance of the rental agreement or as advance rent for other than the next immediate rental period, the landlord or the landlord’s agent shall either:(a) Hold the total amount of such money in a separate non-interest-bearing account in a Florida banking institution for the benefit of the tenant or tenants.

There is also the alternative of doing a step up in the rate after 5 years to encourage them to refinance.

That is the best case scenario, of course sometimes you get lied to and stalled, that's why it is important to always emply a double strategy and stay a step ahead.

I also have $100,000 in the bank, and I'm trying to figure out what steps to take next.

I always remember that rockstars know rockstars, so find someone who is a mover and shaker - likely a meetup host - and then ask them who they know.The people doing 100 flips are super busy, so I've also found the best person to find is someone who is a step or two ahead of me...so maybe for you, that is someone doing 2-3 flips a year. 

Besides registering with the city, are there any other steps required to setup as a STR/Airbnb host in Alexandria?

Thank you for coming back and clarifying it, the minor difference does make a difference to me in practice.   

Aside from what everyone else wrote, note that adding units require various steps that you may not have considered (e.g., adding a new street address with USPS, etc.).

With many of the investors I work with the number one fear is :  Taking The First Step and saying YES. 

These larger projects are going to have a lot of steps.