We completed the work 2 weeks before our baby was born so we took a 4 week hiatus to rest and have the baby.Then I dove into the design, planning, and permitting for the basement.I visited the local Permit office in Alexandria and basically said, "Hi, I'm a new homeowner and I'm an idiot when it comes to permitting.

Some will give you costs based on no permits, which will likely be lower.  

If the lender does not permit this, your attorney and CPA will have limited options.

Duplex have different zoning that may permit additional units.

It sounds like you can not for any purpose since the conversion is not permitted.

Have you checked the local regulations if STR are permitted in that market and what the process is?

Postal permit $220 per year.  

I have started soil tests on 12 lots costing me a total of $5340 for the permits.

Verify STR regulations in Littleton/Denver and secure permits.

Connect with local investors and experts for a house-hacking strategy and ensure proper permits for rental properties.Good luck!