It happens to be in the same ZIP code as West Hills, so Zillow uses comps in West Hills worth over $200k to comp my property which isn't a comparable property.

First place I'd start is with the City, specifically Code Enforcement.  

Keep this in mind the next time you find black mold or carpenter ants.Final thought on the owner not doing routine maintenance ... if the house if older than about 20 years then you need to check all the mechanicals (plumbing, electric, HVAC, low voltage) for code, quality and function.  

There is no replacement for looking up the city zoning code and seeing what it says.

My go forward strategy is take these homes that are in good condition, maybe even lightly renovate them and turn them into standard rentals, on the older ones there still may be resale or scrap value I'll take that on a case by case basis and then begin to Vet incoming tenants and establish a "housing code" so to speak going forward on appearance...this will be a multi year strategy as I can't just kick the old homes out and find great new tenants over night but I'm confident over 5 years I will greatly improve the appearance and there for the rent value

@Douglas KrofcheckIf you have four separate units and wanted to install a central vacuum in each, it is possible each would need to be plumbed separately {for fire code reasons} - either back to a common mechanical room or within each unit - requiring a separate canister/motor to be installed for each.While a central vacuum would be a nice perk, I doubt it would be cost effective - it would likely be cheaper to finish all the units with hard flooring (no carpets) and buy a $50 Bissell Power Force bagless vacuum for each unit.  

I am looking to put offers in an entire zip code in my area.

You need to immediately sit down a learn the Ontario codes and attend a few local LTB hearings to get a feel for how they work.

It's a revolving door,, If you choose to do this rent by the room, you will need to put a room number on each private room so if you ever have to file a eviction the room is designated,, I would suggest the electronic key pad type lock for main entry and one for each private room so easy to change codes.

Unless you are familiar with codes and the correct way to do things.