I’m actively seeking to purchase either a multi-family or duplex unit in the Columbus area  for a medium rehab project. 

Purchase price: $55,000 Fix and Flip Purchase.

@Brian DolbeareI have never purchased a property with no off-street parking.

Purchase price: $415,000 Cash invested: $90,000 MY FIRST RENTAL PROPERTY !!

I am thinking about purchasing land for the intention of using it as a RV & Boat Self Storage.

Hello Doug, I am not a real estate attorney nor is this legal advice.Unless someone's state has specific laws banning contract assignments you should be fine doing the following.  

I'm considering purchasing a condo or a small SFH in the Oceanside/Carlsbad area as an investment property and renting it out on a short term rental site like AirBNB. 

This doesn't replace the need for a MSA that will capture additional clauses needed on a Contractor-SubContractor relationship, this is just a project specific form you would use in addition to the MSA (prepared by your Attorney):This template is for informational purposes only and does not constitute legal advice.

3) Any specific states you recommend to set up any of these (Not sure where I'll be purchasing property yet, maybe Detroit, maybe Cleavland, maybe Augusta, maybe Des Moines, maybe Saint Cloud, maybe Memphis...)4) I already have a LLC based in Hong Kong (We call them limited companies, but the principle is the same).

Specifically, what research results told you these were two good cities to invest in?