There was also a loan grant available from the state of NH for first time home buyers for 3% down payment assistance.

I assume you’ve got a loan that says you will be living there.

You need two years of steady income before you can qualify for a loan.

Consider using an FHA loan to secure a 1–4 unit property with just 3.5% down and take advantage of tax benefits by living there for at least two years.

And could even get a second home loan if doing traditional financing.

This vary heavily town to town. 20% down is great if buying strictly as investment but if you have a way of owner occupying I would explore that route and apply the 20% down to increasing value of property and instead using low money down loan. 

., Purchase Price: $475,000 ($197.9/sq. ft.).Estimated Market Value: $402,000 ($168/sq. ft.).Financing Terms: 2% interest rate, with a 9-year balloon.Unit B Income: $2,049/month (Section 8 tenant through November 2025).Unit A Income Potential: Similar rent or higher; Section 8 cap for the area is $3,234/month.Monthly Loan Payment (P+I): $1,386.Cash Flow Breakdown (if both units are rented at $2,049/month):Gross Rent: $4,098/month.Vacancy (10%): $410/month.Operating Expenses (37.3%): $1,376/month.Net Cash Flow: $943/month.Key QuestionsWould you be comfortable paying an 18% premium for financing at 2%, especially in a market where current mortgage rates are closer to 7%?

There's no current loan on it right now.

Long term buy and hold RE in good locations is probably one of the lowest risk investment vehicles IMO, similar to blue chip aristocrat stocks except even less risky because even long-established companies can go out of business but real estate very, very rarely ever goes to zero. 

We approached the existing lender for a loan assumption.