It’s important that you have these things agreed on ahead of time.Just remember that legal entities are not eligible for conforming residential loans.

A 20% down conventional loan is the only conforming loan option if you aren't living there (unless you can call it a vacation property somehow).Does that clear anything up? 

Keep in mind the conforming loan limit in LA is 765k.

These homes would all be considered as "one generation" of home by the appraiser because they are in the area built between 1918-1935 and conform to that norm. 

I should say that you can cash-out sooner, but you're restricted to using the value you purchased the property at, not a new ARV.You could also explore finding a local bank for a portfolio loan; since these are non-conforming loans they keep on their own books, they make the rules entirely... including how long you have to wait for seasoning. 

I would think I could package the primary and Heloc into one conforming loan up to the jumbo limit and then get a Heloc on the percentage above the jumbo limit?

Pre-COVID the conforming loan lower limit was $50k, ie you can't get a mortgage under $50k. 

Even if the area is zoned single family residential, the person that built the secondary structure could have received a variance to make it legal non-conforming,

*shrug*The good news is every insurance, boiler, city code, fire marshall, nuclear board, etc inspection I've dealt with resulting in pass or fail with detailed list of non-conformances.

We kept the integrity of the original design, modernizing the floor plan with a more conforming staircase and conforming floor elevations.