The reason that the current owner is selling it at such a low price is it's going to be a major pain handling the eviction process & turning the unit over after you finally get this dude out of there.This right here is how we make the big bucks in this business.

It was a pain mapping out a system to manage such a demanding tenant pool. 

Is it less of a pain if to get a second property with an FHA after Homepossibble versus refinancing out of a FHA to acquire a second FHA?

These are useful for low-use various building supplies that can be affected by moisture, stuff like drywall tape (especially the composite tapes), fasteners (that weren't sold in the big buckets), various hardware (still in clamshell packaging wherever possible), any sort of rubber or vinyl hose, etc.Larger supplies (rolls of tubing and electrical wire) go in garbage bags.Sheet good like OSB, plywood, cement board, and drywall are a real pain.

Be cautious if your planning on making a second illegal unit, I can't emphasis how much of a pain it is if the city finds out.

Definitely a pain in the hind end for you and will cost you some money. 

But 12% + 15.4% makes for a painful tax pill to swallow.

I had forseen this years ago but I aways thought the pain in the tail of reading meters and billing tenants was too much work vs. charging more rent. 

Every city has pain points and issues.

I highly suggest you get in touch with your network and find out building code, what sort of structures you can put on your lot, and what the safest, best options are**NOTE** A container is NOT a secure choice UNLESS you take pains to make it secure.