Need Advice on Assessing Development Options/Feasibility

[Kevin Yang]

Appreciate any advice here! 

In Sherman Oaks, California at a LAR-3 zone, I have a 7, 200 square foot lot with 3 units - one with 1 2 br/1bath and two with 1 br/1bath.  These are renting out at a total of 4.5k per month and am paying 2.5k per month for mortgage.  Net income is steady at around 1k.  To be honest, there's a lot of wasted space there and it's all single story.   I have over 400k equity built up for total value of at least 850k.  

Right next door to my complex is a slightly larger lot with a 7 unit building, each renting out for at least 2.5k with a total rental income of at least 17.5k per month.  

This makes me think I'm missing out on an opportunity to develop or at least assess development.  I do have some cash to invest and want to evaluate my options. 

However, I have no experience with development and am looking how to get advice on how to best calculate key indicators on making an investment decision. 

Can anyone help advise with the following? 

a) How to best find someone or research a way to evaluate development options including cost, etc. of developing an apartment building, given regulatory and other restrictions?  I'm looking to do this at a high level initially and low to zero cost (don't want to spend a ton of money on an architect when I just need to assess feasibility). 

b) After the above is done, how can I best evaluate, using key financial indicators, etc. to make decisions.   There's of course other options I can look into such as remodeling the current, 1031 exchange, and so on which also needs to be compared against later. 

Thanks for the help!