You could also offer to cover part of their tax liability through negotiation or encourage them to convert the property into their primary residence to use the IRS exclusion for up to $250K/$500K in gains.

Let any potential renter know that you intend to convert the garage into an ADU and address any potential issues created by adding the ADU (parking, shared yard, quiet hours, etc.)

First, obviously leverage is the MVP, but this isn't my first interneting, I know controversial titles get more attention.Second, I’m a recent convert to Pocketarianism.

We have a lot of owners convert to Mid Term or Long Term rentals.  

When I encounter this type of client, I do everything I can to convert them into one of the previous clients.First thing I have them do is run all their income and expenses through a separate account instead of their personal account. 

One where the lady was promised by seller and seller's agent that it could be converted legally.

I have a PO Box that i used for that purpose and any other business mail but since converting to ACH i am not sure when its the last time I went by the post office.  

Remove the kitchen all together and convert it back into two duplexes or is there another option?  

Love seeing good things happening in a neighboring city.Curious, you mention converting this to apartments?

You won't be forced to de-convert unless you have violations...eventually the city will start fining you.Very critical terms are non-conforming (no violations - grandfathered in) vs. illegal (violations)...