Wow, thank you everyone for the input!
I spoke with a lawyer and he pretty much confirmed Michael's opinion on pursuing it in court; pursuing anything under 100K is a loss, so I'll likely sell unless another opportunity presents itself...
Feel free to send me your best realtor recommendations!
Here are some answers to the questions below.
Eric:
I'm looking into getting an estimate this week, but I speculate at least 50K-100K based on other comps in the area (although I'm not sure how much in dollars any of these issues would factor into the pricing from a market stand point of view, other than to negotiate in the worth of cost and risk to the buyer).
Ali:
Getting estimates from GC's and architects has been a little bit of a challenge with quotes all over the place, as I find them a bit reluctant to work out multiple plans and prefer to focus on one at a time. Will definitely check out the @Jeff Greenberg meetup next month, thanks!
----Maybe I should just keep calling around/find better contractors?
Dennis:
For the scope of construction deemed necessary by the city, it's hard to be certain without shelling out another 10K-15K for architectural plans and holding costs. All of the building plans and documents I've gathered are tiny plot plan sketches at best with some poorly written cursive squiggled next to it for the description. My best guess is that someone converted a kitchen to a bedroom and cut a doorway into the diving wall between the to two units. The issue seems to be less of a structural issue and more so due to a lack of paperwork ever existing on the house, period. Everything comes up as inconclusive when I bring it to the city for them to examine.
Matt:
My inspection didn't mention anything about illegal construction, just said "as-is," which I guess technically there is legally no such thing in CA, according to the attorney I spoke with.
Joseph:
Checked out the link, seems pretty interesting but there are a couple of hang ups I see myself getting into as there have never been any legally recorded tenants on the property in addition to being forced to provide section 8 housing, which is a less attractive option. No go on AirBnB, highly frowned upon by the city with crazy rules and fines. RSO technically means I'd have to pay every guest a relocation fee (up to 20K/family).