I've seen this happen in my area where the bank owned the property, thus having the exemptions removed and the property appraiser reappraising for value, that higher value is now taxed at the tax rate rather than a lower value being taxed at the tax rate.You could also call the tax collector office they are very amenable to helping out when investors call with questions. 

No mistake on plans, debating making it a office/nursery.  

I also look at the credit report and check the income to debt ratio as a loan officer would.

The absolute slam dunk is professional offices.

An informal probate would be available to a decedent who's asset total less than $150K.Ask you seller if the decedent owned other real property and stocks, etc. estimate what the total vslue of those might be (roughly) and then ask your title insurance officer what they require. 

The hardest part of this is probably making time to go to the attorney's office and sign documents. 4.

Some Post Offices will allow you to list their physical address if you have a PO Box there.

If you call your local county building or sheriff's office they will be able to tell you what you need.

Have you thought about "interning" at a real estate office until you turn 18 and then getting your real estate license ?

i.e. residential, retail, office, industrial, owner occupied or tenant occupied or others?