When i bought my first apartment and was handed the existing leases I knew I had some work to do when they were only one page long. 

BRRRR is common in commercial and your existing lender will need more of an appetite for a refinance if they know that they are going to loose the loan.Fannie, Freddie, and some local/regional banks actually have a supplemental loan feature that facilitates a BRRRR...the original loan stays in place and you get a supplemental loan when the property has been re-positioned, rents raised, and stabilized.There are also construction/perm loans where rehab is financed during the IO construction period and then the loan starts amortizing later. 

And what will that do to the existing SF housing stock?

You just to properly describe the “proposed” piece you are trying to buy.....dimensions, reference to existing lot lines/corners, etc.

@Paul SchaefleI would start by contacting the village and or Hall and see how they regulate and if they do regulate short-term rentals.

You do not need to give a reason for non renewal unless your state regulations say otherwise.

If it's small enough, there are exceptions, or exemptions, and depending on the location of the investors and property, only state "Blue Sky" laws may apply, as opposed to the federal SEC regulations. 

Pay down existing debt.

I do not see why you'd have to wait to refi your existing property, but purchasing another as owner occupant would likely be problematic unless you have some valid exception / circumstance as to why you cannot remain in the existing home for the required year.

I am looking to include regulations for a duplex about parking and property maintenance either in the leasing contract  or as an addendum to the contract.