Of course new construction would be expected to be at code.So this is what I would do:Learn the 6 CA ADU regulations to some extent: AB68 (this one may be most important because I assume your addition is attached), AB881, SB13, AB587, AB670, AB671.After learning the 6 ADU regulations at a high level, I would determine if the JADU/ADU option is the best option for you. 

No matter what socio-economic level, I think people can make the best decisions for themselves. 

My monthly student loan payments are based on a percentage of my adjusted gross income, so in order to get those payments down to a manageable level I always max out my retirement funds.

Now it is noted on inspection, that the wood floors are sloping as much as 2-3" out of level.  

More things impacted my current mindset, and at a high level I just want to get to the point where my mother does not have to work anymore, and I can give back to my community and enrich other's lifestyles. 

Not only can it provide stability and security but lower my stress level.

Retail at ground level,  apartments on second level.    

Housing cost should not be more than 1/3 of a indivulaes income otherwise they can not afford it.Going above that level is why people choose to live pay check to pay check.People rent ether because they are saving to buy, prefer to rent or rent because they are living beyond their means.

Or, is it that they are afraid to take it to the next level?

Depending on the profit level, I would maybe consider doing it as a Limited Partnership.