Do I have to register a motor-vehicle to travel on U S roads?

Good luck with that. Any vehicle operated on the roads of Florida requires registration and tags.

I own my mobile home outright, but the land it sits on is rental property.

You'll have to examine the terms of your lease. If the well is the sole source of your water, it may be a requirement that LL fix it under Chap 83...

According to Florida law all businesses of any kind need to be licensed. Therefore is a landlord renting property a business,

Your premise is technically incorrect as not ALL business require licenses in the sense of a regulatory license as opposed to an "occupational"...

If you are going to do any appeal it should be with a competent appellate attorney. This is critical as so far self lawyering has resulted in a...

If a vendor does not pay for the software I developed for them, would I be liable for throwing a "kill switch" to disable it?

I would not do this as you would likely find yourself at the wrong end of a lawsuit for tortious interference with business relationship or similar...

Up lease expiration, tenant moved out without paying last half month rent and no new address left. How to collect the rent?

Absent the 1/2 month rent being in the thousands of dollars value, you will spend dollars chasing dimes pursuing this. Only way to really address...

DO you know any Lawyer's that would take my brothers case pro bono? In jacksonvillle Fl

No. Not on these facts unless his name is Roger Rabbit.

Your lease agree is the stating point for your answer. Many leases for single family homes shift the burden to the tenant for pest control.

When is someone deemed to be in possession of a real property?

You need to explain the context of your question, as its way to vague and confusing.

What are the tenant rights when breaking a lease 3 months shorter but proving the landlord with a new tenant for that time?

This is the peril of "from what I read" without being a lawyer, while its good for learning questions to ask, always be wary that absent speaking...