Surveying has a lot of 'art' and nuance to it as well as the mathematical component.

So the DSCR’s PITI component is based on the payment as if it were a 30 year amortizing loan right?

The other component that makes me nervous is how fast properties have run up over the past 3-4 years and will that leave any appreciation for the net 3-5 years?

As an individual landlord, especially one managing remotely, it might be challenging to secure similar terms.Payment Trust: Vendors may also be hesitant to extend credit or prioritize someone they are unfamiliar with, particularly when the owner is based internationally and payment assurances are less certain.Real-Time Issues: Handling urgent maintenance or unexpected issues can be cumbersome without a local presence.

Are there any unexpected benefits?

Having a stable job can help you handle unexpected expenses and save for buying new properties.Many new investors are often looking for deals with good cashflow, but these are usually in less safe areas because they come with higher risks then investors are expecting higher cashflow.I suggest focusing on the long-term growth in property value rather than immediate cashflow.

You will need a safety net for unexpected expenses (repairs, vacancies, etc). 

Could someone either give me an estimate of average lifecycle for common components of a house within Florida, or recommend any local contractors that could give me an affordable inspection report?

Show up unexpectedly and let them earn your trust don't just give it out right away.

One issue of doing it within 401k, is what happens if you spend all your money from there, and then have unexpected expenses or lower ROI than expected.