Commercial inspection requirements are federal not state to state and can be found at FMCSA.DOT.GOV
Your question is not very clear as I live in Florida and I do not know what kind of strange laws you are talking about.
No. Florida wouldn't pass any such law unless it was passed as a part of the Federal Motor Carrier Safety Regulations first. As it, the FMSCR has no requirement for commercial vehicles to have air conditioning.
Recreational vehicles are dangerously unregulated, and will continue to remain so until senior citizens and the AARP lose some political influence. If it's a registered recreational vehicle, it's exempt from regulation by the FMCSR (the laws which regulate commercial vehicle operations). Licencing requirements become the jurisdiction of the state in which the vehicle's operator is licenced, and they can only apply those requirements to residents of those states. California has their own state licences for vehicles over 26,000 lbs. which aren't for commercial use, whereas Florida allows you to operate pretty much any vehicle exempt from CDL requirements on a regular drivers licence. If a Florida driver operates an RV in California, then California must recognise it, and cannot impose additional requirements on the Florida driver.
Florida, like all other states, requires that all drivers be insured. The state has set minimum requirements that apply to vehicles that are owned outright (no financing). You can review the Florida requirements here: http://www.flhsmv.gov/ddl/frfaqgen.html
The only two states I have encountered are California and Florida.
There are no special requirements for US Citizens.
You need to be more specific. If a truck of some sort, the answer would be commercial lines.
"In 1981, then-Gov. Bob Graham and the Legislature halted motor vehicle inspections after complaints about long lines at state-run inspection stations." I found this a web site!!
on products, not vehicles
California has the most motor vehicles registered
FloRida
You should Inquire at the Florida Department of Motor Vehicles.