If you are doing plumbing or electrical then definitely will need a permit.

Lastly, you have to get permits from the city to convert an SFR to a duplex.

True that currently, my schedule will not permit me to be personally involved in any sort of rehab or similar pursuits, but it (likely) won't always be true and ownership is simply something that I'm passionate about. 

Today, it's hard for builders to get horizontal (development) financing on permits and infrastructure on long plats (10+ lots) and this is keeping supply low relative to demand.

Permit databases are a rich trove of detailed data, and often include phone numbers not found in any other data sources.

The loan option is available with a 401k (assuming plan documents permit that) and the loan is limited to $50,000 or 50% of the balance, whichever is less. 

I'd only buy the properties contingent upon getting a building permit for what you're trying to do - if by chance you're unable to get your permits your project could be a real disaster.

I would agree and my gut feeling is that by the time you do the addition, repairs, permitting and inspections the 90 days will go by anyway.

We need to apply for building permits and the architect that we've used in the past has proven to be unreliable so far and we are looking at alternatives. 

I called listing agent and he said there is a 600K lien and mentioned a bathroom which was built without permits.