In order for your scenario to work, you need to purchase a property at a cost low enough that after you rehab the property you will be all in at less than 75% of the ARV (I say less than 75% because you also need to factor in the closing costs for the first loan and the refinance).  

We have 3 homes leased, 2 rehabbing and a seller financing deal for 3 doors in a multifamily.  

The listing agent for the most recent estate was able to petition the county to have the address changed, and only then were they able to sell it, since then when you googled the address none of the news stories about the house would come up.

Most banks will do a commercial loan on an investment property for up to 90% of cost (purchase plus rehab) quite easily.

Has your rehab raised its possible sale price by a LOT more than what you put into it? 

If you consider a straight rehab to lease deal where the numbers don't quite work as well, and go the lease option route, yes you cap the upside but you also limit the downside to as degree.

I would like to know if I have to switch my mailing address to the duplex if i only plan on living there a few nights a week throughout the year?

In my experience even if you go with the older property and completely rehab it you can still have issues pop up.

Did you pull my address out of a hat? 

I work with national cash offer to acquire properties and we also do a few rehabs.