In Raleigh, NC I believe there is a city ordinance that limits the amount of unrelated individuals living in a house to four people. My question though, does overnight lodging (eg. Airbnb) count towards unrelated indi...

You should be able to at least have some good rapport and understanding with them while you're co-habitating. 

The short and simple answer is yes you can cosign/coborrow (difference is you're on title and loan instead of just loan) depending on the type of loan you engage in, FHA, Conventional, VA, etc.You'll both need to have min qualifying credit scores which is typically 620 + (some programs down to 580).You can use your income to help her qualify.I assume you'll be cohabitating the home with her as well?

Co-habitation is the problem. 

But what if I did not want to live in a multi family unit.The reason I say that is that I don't think my wife and I would like to be in a situation where we were kind of cohabiting with other tenants.

Peter wrote a book titled Abundance that spins a very positive outlook on humans' future cohabitation with tech.

Your tenants co habitational relationships is none of your business.

It is not usually the actual cohabitation of too many people that prompts complaints, but rather the actions of these cohabiters.

Replace ESA with black / family with children / unmarried cohabitants / homosexual / etc and this tactic has been used before.

Purchased as a primary residence and turned into a rental when we cohabitated.