While both involve finding and properly securing a site and bringing it to full entitlement, the ground-up process includes the land piece but gets way more involved and complex to execute.The full "Monty" for ground-up development needs to include financial literacy, an explanation of metrics, and how they work.

move downtown into an apartment.

Final comment, it seems complex.  

Going into the unknown and buying multiple SFHs/duplexes or an apartment complex OOS and my property taxes will skyrocket (property tax is reasonable thanks to Proposition 13 in CA).

I fell off the wagon when I saw a bullet point that indicated all second story apartments have an elevator and their suggestion that it was possible to get 1000% Plus Potential Cash-on-Cash return in the 1st Year.Where has SCDC built?

I would have just filed a lawsuit against them and took it from there.This situation is quite complex.

Or paying off my debt, while I provide them with a nice house to live in instead of an apartment. 

I wanted to see if anyone is familiar with or can recommend paid mentorship programs or coaches for small multifamily unit investing (2-4 units).In my research, I’ve found that most mentorship programs or resources I come across are geared toward large syndication apartment building purchases or other types of investments, such as short-term rentals, medium-term rentals, single-family homes, Section 8, or fix-and-flip projects.

There are two, one bedroom apartments on the second floor and first floor is currently being used as a convenience store.

From there, I would like to consider a 1031 exchange in the future to acquire more units.My current property management company suggested that they could handle a mid sized apartment building but I would absolutely not consider them for it as I believe they have overextended themselves and communication is lacking.