@Leonce Barrigah, Based on the information you provided, it sounds like your lot is technically zoned as C1-2; however, it has a legally existing, non-conforming use of a 4-unit residential(Residential units are not allowed in Zone C1-2).

We still don’t technically even have 20% paid into the loan so we still pay PMI insurance every month.

My sister is going to college in northern Utah next year and I was wondering if I could co-sign on the loan to purchase a house so it would be her primary residence and she would be technically house hacking it but I will be providing all of the financing for it.

I have never done something like this before but I spent a lot of my professional life talking to others, teaching classes (technical) writing white papers and the like so I am people person.All you really have to do is make sure you can get good systems in place.

Can I still list it as my primary residence during the refinance process (it technically really is) even-though I'm leasing it?

Also, I understand that just because it is no SPDS, they aren't relieved from disclosing known issues if I specifically ask, But dont fully understand the technicalities of this.

The MLS is actually not a good source of comps, technically, because properties on the MLS have not sold.  

If you go in there and remove items and the dog she may have a financial claim as she has not technically handed over the property and is a holdover, this could be a trap.  

I'm seeing quite a few of these types of properties for sale, but mostly they seem to be the type of property where the units are not separately metered and I'm not even sure if they're technically legal.

My goal is that illusive financial freedom, I don't want to work a "9-5" anymore (technically I work 10PM-530AM..... it's rough), and I don't want to work for someone else anymore.