However, a recent lender I spoke with said that was not the case (for that lender), and that they would perform a market study for the units and loan on that.  

Does anyone have an MS Excel model for Property Development Feasibility Studies?

.- Know that it is possible to have a tax sale later ruled invalid (usually because an interested party claims/proves they weren't properly notified of the sale). 

In the process you'll get an FHA appraisal done, if the appraiser notes  a second kitchen you will have to prove multi-family zoning or the reverse won't go through...or you can rip out the second kitchen.  

although I don't know of any specific studies, I have thought about this for the Bay Area.

You know the Chi is all about show and prove so learn as much as you can and do a lot of research and base your decisions on facts is my humble advice.  

After finally taking the time and studying I passed my ca real estate exam.

I think there's a few people that you should study and avoid some noise@Ken Rishel Mobile homes regulation@John Fedro Mobile home space marketing@Jay Hinrichs transactional funding flipping@J Scott read everything is written and buys books on BiggerPockets on Wholesaling flipping, don't ask wholesaling  questions on these forums until you've read everything he's written and read his flipping book and his renovation costing bookYou could read my BP blog on seller financing and joint ventures home sellers, money partners, private IRA lenders, and other creative ideasDodd Frank and safe act are not the easiest laws to understand and I highly recommend that you use a registered mortgage loan originatorLastly buy the real estate agent books in your state and know the information. 

If you are okay with living in the duplex, let it season some, and, as mentioned, keep saving up for the down payment on the next one while studying the market and expanding your landlording skills--both on the ground with the duplex and with books (I have a Classics of Landlord Lit" blog post, but you may have burned through the core reading). 

That's the best way to prove to investor clients that you know what you're doing.