Finance building second unit on same lot?

[Evan Reimondo]

Hi all, first time poster here, please forgive any ignorance! We are just finishing a cash-out refi on our primary residence with the intent to use the new cash for the next investment. Part of the appeal for the current lot is that it is zoned multifamily and we could build a second house on it. What's the best way to finance the second house that minimizes cash out of pocket? Are we able to use a standard a construction  loan to build the second unit, assuming the new build would become our primary residence? Or would we be creating something weird or unworkable because that would mean two separate mortgages on the same lot? Or would it just mean that we'd have to refinance into some type of commercial loan at the end to cover the whole property/both houses?  I appreciate any and all suggestions or links to good reading!