Also read through the HOA covenants and make sure multiple unrelated people are allowed to cohabitate.

As a person with extensive use experience of such, I will say at worst would take maybe as much as 1hr to track an heir, emphasis on "an" as the correct tool in this arena, or more specifically the one I used, I could dig up the last 30 years of a persons history, every address, co-habitant, everyone in 1 degree of separation, there 30yr residency/ work. sphere and so on and so fourth. 

You could ask a lender if this can be done though being married would of course raise some eyebrows as it's assumed a husband and wife would cohabitate.

We spent the last few years cohabiting with other people to save money so we are not interested in house hacking - that being said, if the numbers really makes sense to do this, then we would be open to looking into this again.

IRS states you must and your spouse must have co-habitated in order to receive the exemption, although it clarifies that you didn't need to be married at the time of co-habitation if you married after.

If no lease is drawn for the friend to "live" with the owner like the tenant above than this seems to be a home that is cohabited with the friend helping out with the mortgage.Now I am by no means trying to spin the situation, but based on you saying that you have had investors get nailed for not disclosing rental income where they living in the home as well?

MH's cannot be moved... the only way they can be replaced is to dismantle on site.Not worried about tenants they cannot live any where else in the state of Oregon for less money unless they co habitate with others.

Just write your lease with both listed as tenants (joint and severally clause) , you don't have to worry about their relationship unless you are in an area that does not allow cohabitation.

My largest apartment is a 4 bedroom, but since one bedroom is very small and the city won't allow more than 3 unrelated adults to cohabitate where the property is, I have been renting it as a 3 bedroom. 

I agree to that in situations of co-habitation, both occupants share liability exposures.