I would speak to a local realtor that can advise for what to build that would be in demand 

All of the listings are the same, fake.Go to local meetups without an ask.

I already have a B.S in Engineering (~10 years ago) from a 4-year university, so I'm thinking to enroll at a local 4 year University that offers a minor program in real estate.

I'd also suggest reaching out to a local agent in your target investment area - they'll have good referrals to provide you for your lending needs. 

Also, none of it generally, unless your local municipality reuires otherwise, requires a permit. 

I'm local.

Noah, I would call the local officials and ask them for your options.

I follow several local areas and the site tells me that I am not following any locations. 

Like @Bruce Woodruff mentioned above, get a plat map (not a typo, its a property line map) from the local assessor's office, planning office or county clerk and give it to the surveyor. 

I see you are local to the Tampa area too.