What are the city code and permit requirements if any?

We have a glorified house hack scenario in Portland where we rent about half of the property out as a mid term and while our travel nurse is working we are improving the second half of the property for a future permitted attached ADU. 

The house is mostly turnkey, with the seller having installed new carpet.However, I've heard concerning stories about tenants and their pets damaging carpets, even if pets weren't permitted per the lease. 

The ordinance may require a permit to be obtained for the creation of a junior accessory dwelling unit, and shall do all of the following:(1) Limit the number of junior accessory dwelling units to one per residential lot zoned for single-family residences with a single-family residence built, or proposed to be built, on the lot.(2) Require owner-occupancy in the single-family residence in which the junior accessory dwelling unit will be permitted.

My goal is to build a substantial portfolio, aiming for two more houses by the end of the year and continuing.As a newcomer to Detroit, I am seeking your insights on the best areas to invest in.

Power of attorney is not permitted, but I did have one lender who blessed off on a corporate resolution for a stateside entity member to have signing authority for the business.

Have you (or anyone else) seen a municipality where they had a permit process allowing non-owner occupied STRs, then they changed course, prohibited STRs and did not grandfather in existing licences?

I would get a lawyer involved and have clear documentation with the town zoning/permits.

I've read the reports that talk about the permits pulled recently and overbuilding of multifamily, but I can't find whether those are big complexes or smaller. 4 units and less would qualify for residential financing, but is there a reason that I can't find anyone else building these?

Submit either for variances/reasoning with city or go direct for building permit approval7.