Loving this discussion! I can answer a few pieces of this.
"For property management cost would this typically be taken into consideration for the NOI?" - yes, both in theory and in execution. I'll admit I'm not so sure on a very small deal like this, but at the institutional level, commercial tenants all pay their pro rata share of operating expenses (OpEx) (also called CAMs), and that usually includes paying for engineering and property management, among other things. On a small deal like this, it might just come in the form of a management fee calculated from gross rents or NOI.
"With being in a historic district would you have to consider higher maintenance cost for major CapEx expenses?" - it completely depends on what the city requires when you do work on historic buildings. You're going to want to talk to a savvy general contractor that operates in that city to find out what it's like.
"What are the factors or calculations do I need to consider when underwriting a deal to decide if the property is a fair value and worth pursuing." - I think the biggest thing you're going to want to do is get a good estimate of how much capital expenditure (CapEx) you're going to want to spend to improve the property. It might not be right away since it's leased up, but once you get a vacancy or two, you're likely going to need to spend capital to get it competitive to achieve market rents.
Also, ProTip: If you're local, walk into the businesses and get a feel for how things are going. For example, if it's a coffee shop, buy a coffee, leave a nice tip, and ask the employees how business is going and how they like their job and the community. You're almost certainly going to learn something valuable that you won't get from the broker, the seller, or any docs you review.
I'm not a lender or a dealmaker in this space, but I'll echo that I think you'll probably want to get to 40% down or more.
Lastly, also if you're local, drive around this part of town and look for the "Professionally Managed By" and "For Lease" signs for similar properties. Contact those property managers and brokers and ask them how the market is going. You might connect with a broker/PM with great rapport that you might want to hire on as PM.