The 4th apartment definitely looks like it's not up to code because one of the entrance doors has very low clearance (like less than 6'5").Thoughts?

There are separate entrances, stairs have been blocked off and is all legal.

Grant, if the house is vacant and liveable, I generally find that a sign in the yard which says "House for Sale....Owner Financed" plus a few more at the entrances to the neighborhood, is sufficient to get my phone ringing off the hook.Does the local Real Estate Lawyer happen to be Scott Horne?

This 3/2 has the added bonus of a fully refurbished garage studio (1/1) with a private entrance and an outdoor space.

can't even pull a car into the entrance. 

Also behind the property is an entrance to a developed gated residential community.

Although it has 2 entrances and exit-able windows,  I'm fairly certain the basement is not zoned for a unit, so leasing it may not be possible.

It would be different from the standard below.This is what I found:Four things a room MUST have to be considered a bedroom: Entrance: A bedroom needs at least two methods of egress, so it should be accessible from the house (commonly through a door), and then have one other exit (window or door).Ceiling Height: A bedroom ceiling needs to be at least 7 ft tall.

Just be wary of the ones that charge entrance/membership fees.

It is zoned R-2, has a finished basement and has a back entrance that we could close off from the main floor so that could turn the downstairs into another unit and do a house-hacking type thing while we lived there for a year.