That's why you need the HOA, because they implement your private CC&Rs which allow for the greater density...so ANY townhouse/condo you buy you should have anticipated that there were likely some shared services...if there weren't then you wouldn't need the HOA...

I'd love to get in touch with a mortgage lender to see what do I need to get approved for this kind of loan.

Once you have your team: Realtor, GC, Title Co, Lenders, etc.. and you feel like you trust them, then move forward from there.

If it ends up being an expensive or time-consuming repair, you may be able to get bids and have the seller escrow 1.5x or of the bid cost to do the work post-close with a signed agreement and lender approval.  

I've been using FCI Lender Services for about 5 years and find them to be very investor friendly, especially for newer/smaller investors. 

The lender would have had an appraiser issue a opinion of market rate rent for the apartment on your duplex so that's a start on what the rent should be.

I run a small private real estate investment club and we love to plan happy hours for visitors to Milwaukee.

Did you work with any real estate professionals (agents, lenders, etc.) that you'd recommend to others?

Hard to say right off the bat which is a better option since it depends a lot on what you are looking for and your situation but speaking with a lender that understands the application of primary residence loans in multifamily will be important to help you find the right option.

I've met partners, lenders, contractors, essentially my team and its been incredibly valuable.I also recommend finding someone in your market doing what you want to be doing at a larger scale and figuring out a way that you can provide them value.