From what I understand Arlington has passed an ordinance that will begin near the end of the year that requires a permit in order to operate an AirBnB if it is not in a "tourist zone" which they designate as with 1 mile of the major attractions such as the ballparks etc.

In Ontario we can evict if we have a building permit to do extensive work.

My question is basically, what would be a fair monetary breakdown if I will be providing the funding (permits, city fees, plans, public works, and the actual construction)....my ballpark estimate is that all this will cost 2.2-2.4 million if I build nice quality townhouse style 3 bed 3.5 bath townhouse style units.Should I offer him 70/30?

Failing that, you might have to look for private financing.You should also talk with the town to be sure that the property is permitted for use as a rooming house.

can i rent out any house that i own or does it need a permit or something to legally be rented out?

I also have a property close to 90% occupied that I'd consider flipping to any Bay Area investor looking for a small MF deal (11 units with fully permitted quadraplex development)

They are licensed and insured, pull permits and do the work according to the engineering report. 

Obviously RSO/rent control is difficult to avoid in L.A. and the numbers would have to make sense.2) Find a 3bd 2bth with a detached garage (or ideally permitted guest house) that I can convert to an ADU and live in, while renting out the house. 

I did not pull a single permit for anything, not so much because I didn't want to but because I didn't realize I was supposed to.

The reason I did not identify the buy side first was because I unexpectedly had to sell (special permit on ADU  out of town compliance).