Many lenders allow for low-down-payment options if the rental income covers the loan.You’re approaching this deal thoughtfully, but be sure to communicate the benefits of your offers clearly to overcome resistance from the seller's representative.

I prioritize appreciation, tax benefits (rental property expenses, depreciation), ability to use leverage, and passing on generational wealth with real estate. 

What's the benefit of the $149 sub through TurboTenant?

So there could be benefits from starting a new lease for that reason.

What are the limitations and benefits?

Of course to maximize your tax benefit it needs to be sustainable over time. 

As I wrote in another reply too - one more benefit for me is that in a way it's "forced savings" - I have to find a way to pay the bill...

I’ve never managed roommates or lived with roommates but I know it will benefit me so if  the triplex doesn’t work out I wouldn’t mind having roommates.

.—(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.

I wouldn't suggest you buy a single-family home to live in because the additional cost outweighs the benefits.