I am very interested in the BRRR method for all of my future purchases, but my local bank will not do cash out refi past mortgage 4, and also require 12 month seasoning regardless.  

That's what pays off.Any serious mechanical (elect, A/C heat, plumbing etc) or unforeseen major structural that I can't do well, safely or efficiently I hire lic contractors.

Its good to start and build up some capital but if you are going to be doing this full time you will want to develop relationships with contractors/electricians/plumbers.I usually do the big stuff my self electric/plumbing/hvac and leave the labor intensive stuff to others carpentry/drywall.  

Who in the Los Angeles area is entrepreneurial and well known for their successes with these methods?

You need to embrace the mentality of a student and continue invest in your education, both formal and hands-on, real-world (my preferred method) learning.

It has a lot to do with what accounting methods the bank uses to account for these properties, and that information will never be in your hands.  

On the investment side I think a new agent is less likely to be rigid and is open to creative methods and as a commercial mortgage banker I think that they may still be building their team and are open to working with new people. 

I have efficient methods of rent collection that generates it's own receipt, etc.  

While I invested in my first SFR to start with, after that, I've been able to 'remain' active in the game through other methods - by delivering value.I've been able to create two partnerships while in Korea with people I've met through BiggerPockets.

Referral is usually the best method: ask everyone you know if they know a good handyman.