Columbia Missouri New construction financing for ADU's

[Milton Chamberlain]

Hi all, I own a deep 0.75-acre inner-city lot in Columbia next to a similar lot owned by my father-in-law. THey share an easement driveway. ADUs are very popular there, and we’re looking at building 4 ~400 sq ft units that rent for about $800–$850/month. We’d also add a shared concrete driveway, parking pads, and small patios. Estimated cost is around $90k per unit, potentially ~25% less if we manage it ourselves, plus ~$40k to remodel the front house and increase its rent by ~$500/month.

My wife and I have an S-corp and a dental business, but on paper our DTI isn't great due to multiple properties, loans, and other debt. My father-in-law is mostly debt-free and could partner with us. He has a high income. We also have significant equity across properties we could tap into, but rates are sub 4% so prefer not to.

Are there financing options for something like this without a large out-of-pocket investment? Open to creative structures like partnering with my father-in-law in a new LLC, seller financing, leveraging equity, or using our entities.