Is the 5th basement unit a legal permitted unit? 

This is from the actual rules under personal disclosure PERSONAL INTEREST.No broker or affiliate broker shall, either directly or indirectly through a third party, purchase for himself or attempt to purchase or acquire any interest in or option to purchase property listed with him or with his company, or property regarding which he or his company has been approached by the owner to act as broker, without first making a full disclosure of his true position to the owner of the property or to any prospective purchaser for which he has acted for as a client or customer.

Steel is both usually unattractive, and may have your prospective tenants asking why they would need a steel door (esp if your property is in an A/B neighborhood.

@Matthew Forrest this is a new law for us here in CA so there is still some ambiguity in the process.The lenders we use are saying that they will lend based on the new income (as long as the ADUs are permitted) and essentially count the ADUs as normal units. 

If you've had 0 to a few prospects then it's likely the cost preventing more interest.

You must appeal to the tenant prospects in this area to succeed.

Market effectively, price correctly, vet prospective tenant/buyers, and you should be fine.

In my state they do allow payment plans, but I think once you default on a payment plan you aren't permitted to enter into another payment plan.

The deal hinges on a path of right hotel permit for this asset in a commercial zone.

BrentHere is some info taken from a post I made that may be helpful:"Here are some things to look for from an Insurance prospective:1.Any in-ground tanks (active or inactive)2.Any Knob & Tube or Aluminum Wiring3.If built before 1978, does the building have Lead Safe certifications4.Any wood stoves or secondary heating units.