Initially, our plan was to fix the drywall leaks, clean out the property, and relist it for a small profit.

A mortgage lender can help determine if refinancing or tapping into equity might allow you to acquire additional properties.Consider a 1031 Exchange: If you're open to selling a current property, a 1031 exchange can defer capital gains taxes while enabling you to upgrade to a larger or more profitable asset.

Overall, it's been profitable. 

It’s not just about the profit margin or the cap rate; it’s also about building trust in the community.

Like @Kyle Mccaw noted there is significant value in goodwill and I imagine you profited nicely over this pleasant long term relationship. 

Investment Info:

Single-family residence buy & hold investment.

Purchase price: $90,000

Cash invested: $25,000

Bought a house this fall in Minot for $90k. Currently have it rented and plan to ho...

How can I strike a deal where they can still receive some income from the property, but I can purchase the home and make my share and eventually (1-2 years away) own the home and eventually get full profit from this 8-unit property.

Or use the HELOC to do a flip, use those profits to hopefully pay off or down the HELOC and then purchase a rental.  

Section 8 can be a profitable and reliable resource but it is 'their ball, their court' so know the rules first.

At the current cost to build estimate $150/sqft, It appears a 1500-1700 sqft new construction will need to sale for around 399,9k to make a decent profit.