Adam,
Firstly, I copy/pasted your matrix into Google; you can private message me your Gmail account if you want to take ownership.
All can access it anonymously - and can COMMENT too (also anonymously) here: www.bit.ly/2E6VpYe
Some comments for you Adam.
Adam wrote: I have good insight into the building
Question: Are all of the units identical? Or similar?
Comments: I would highly recommend knowing the 'particulars' of each unit ... and keeping them in front of you. For example, I added a Square Foot column, and a Unit Description.
Assuming that the square feet and unit descriptions are IDENTICAL... and the quality of the units are identical, as are the noise around the building, then the unit rent per month should be the same.
Search out the reasons that you think that units 1, 3, 4, & 5 were vacant for so long. Disrepair? Pocketing rent? Laziness?
Why the difference in rents between #2 and/or #7 versus #8? Did she like unit 8 less? Is there a racial or other prohibited reason (it's illegal to charge more rent in some cases).
Adam wrote: we feel with minimal cosmetic investments (5K / unit)
Question: $5,000 per unit is 'minimal cosmetic' for an apartment that doesn't provide $5k in gross revenue?
Comment: Minimal to me would be something like 10-20% of my annual gross rent.
I would seriously suggest you binge watch something like Restaurant Impossible or Hotel Impossible ... the stuff that their designers do with ONLY some paint and some decorative trim pieces is insanely brilliant. Here are some links that I quickly googled:
www.bit.ly/2N3xk7w
www.bit.ly/2DBnEMZ
Another AWESOME resource is www.houzz.com You can save all sorts of different things you like for free - and then share them www.houzz.com/user/parkerfairfield
Another great site for playing around is Home By Me - an online free site www.bit.ly/2GkwYIY which is great as you can create copies of your apartments. (It's free - and that link is to one of my designs - an off-grid cabin).
I'd use those sites to get some ideas - and then revisit your $5000 per unit budget.
Design Ideas
I would also try to get a local designer - or a design school, and try to get someone to work with you. You give them access to one of your apartment. They design improvements. You pay them a very minimal amount of money and then make sure you advertise them all across your website (or your FB page).
Property Managers
I'd also do a few things with regards to property management companies.
A) call several of the local BEST real estate agencies and ask for the best property management companies
B) call the property management companies and get appointments for them to come by and give you their proposals for 'managing your building'
C) call around your neighborhood and go look at apts to rent in the same neighborhood / same price point immediately; verify that your idea of the 'right' pricing is accurate.
Seller backed financing is fantastic - make sure that the seller can't get the building back easily / at all. Get the contract written by a commercial property lawyer; I'd say that you should find a law firm that has multiple offices ... and even better in multiple states. And not just some lawyer - but one that specials in commercial real estate law.