Welcome to the newcomers!

I would look at two factors, where are young people moving to the area to get work, and where could I get some land that's favorably close to that location that is permitted to do so.

Another friend who directed the environmental permitting for Anadarko in Southern Wyoming spent about 6 months looking before he found something new.I don't see the professional level jobs available...maybe my friends and I are in the wrong business. 

A list of encumbrances on a property's title can also be found in the land registry.A list of building permits, work orders / code violations can often be obtained from a City or Municipality though an access to information request.  

I have a close friend who is looking at purchasing in the Redwood City area.He has found a duplex but it is currently only permitted as single-family home and the seller is not willing to complete the permitting process.My question is: Do you or someone you know, have experience with converting SFRs to duplexes and the cost/time/paperwork involved with that process?

That information needs to be attached to the contract when you wholesale the property along with a disclosure that the buyer will need to get permits and inspections from Code Enforcement to do the rehab.

Also, I'm not familiar with how it works in WA, but is 60 days usually enough time to secure all of your permits, complete a renovation, have inspections done and then resell?

You also inherited their leases so the terms were set. does the lease permit you to collect partial payments.. check that out.. 

"B closing with A using C's funds" is not permitted any more due to excessive abuse by short-sale flippers.

If it says "no pets/animals shall be permitted on the premises", then you've got a great reason to start your eviction.