"Starting Out" is a great forum for newcomer questions as you work down the path of REI.

Would be interested to hear what area of town this was in A client of mine has found success putting her duplex on Airbnb for a minimum of 30 days allowing her to negate the required STR permit.

There is very little except un-permitted 2nd houses on one lot. 

Essentially if the zoning of you lot/land doesn't allow a Hotel to be built then you can not receive a permit.

Lastly paper work and inspections, a GC should know codes and how to fill out permits deal with logistical end of things.

There were Lots of surprises once acquired, ( Rat infestation in AC ducts, bad galvanized plumbing, No permits, leaky roof, foundation issues, stray cat infestation, windows falling out, opossum infestation.

Can you submit for permits on a house you are purchasing before you close?

The panel upgrade will require a permit and the city/county, who will issue the permit, will make this determination. 

Alternatively is there anyone currently doing airbnb hosting in R.B. and how is your experience with the city permits/enforcement been?

The method that you choose on this transaction must be consistent on any similar future transactions.I don't know of any regulation permitting a $0 basis election on property.