His family made their money with W2s and the stock market.

Study the market.

No established resale market 5.

Curious as to thoughts on building ADU’S for equity in LA / SoCal market.3.

As a realtor I am sometimes aware of deals before they are put on (or back on) the market How did you finance this deal?

Every market will vary due to labor costs. 

Quote from @Tanner King: Where are the best places or best ways to collect data on specific markets?

Connecting with local GC groups in your area will help you connect with subcontractors, find out tips and tricks of the trade in your local area (since all areas and their real estate differ slightly).Also, have you considered the motivation behind building a brand-new duplex versus finding one on the market?

This is critical because depending on your future goals and what we think the market is going to do, we can structure everything to keep more money in your pocket for the next deal. 

Do you see any new rental property up in the market has increased rent since L.A. fire issue?