It puts me in commercial multifamily loan territory, which I'm not familiar with. 

Unfortunately, some of the common red flags result from legitimate tax returns and come with the territory.

I'm currently a Territory Sales Manager for a aftermarket automotive supplier and have over 16 years in the automotive/corporate management field. 

Looks like the property is initially cash-flow-negative, doesn't turn positive until somewhere between year 5 and year 10, and doesn't see a double-digit cash-on-cash return until year 30.Although Rentometer can sometimes over-estimate, it does say that the median rent for a 3-bedroom in that area is $1,600:If we make an optimistic assumption that you can achieve Rentometer's median rent rate for all 3 of your units, that at least gets us to positive cash flow territory. 

What province / territory are you interested in seeking guidance for? 

Since we're nearing "Full Gut" territory anyhow, I'm wondering if it's advisable to remove and replace the lath and plaster and replace with drywall.

You need a lender who can cover most states (We lend all US and some territories and are not a bank)  It would be far easier to do this with one lender rather than trying to keep on track with all the steps. 

I currently work as a traveling territory sales manager for NAPA auto parts, and manage all of my units as well.

This is new territory for me. 

Now, as for the repairs, those come with the territory for older properties, so you can do an extensive rehab on 1 of them since you have some experience in construction yourself so that your repairs and maintenance expenses are drastically reduced plus you increased the value of the property.