I'm pretty sure that LAFC and LA Galaxy only participate in EAL for their age groups that are before the start of MLS Next at U13. So, it's just U11 and/or U12 assuming they continue to have those ages. That's why at those age groups, you'll be getting Galaxy and LAFC's top teams in EAL, which may be an attraction for some.For the couple clubs this may apply to they also have teams in other leagues like the NPL's, socal disco, etc so which is there first teams? In EA or those other leagues.
LAFC doesn't have 2nd teams yet, so it's either for ages that don't play in MLS-NEXT or just the affiliated Socal Youth players.
Galaxy don't know yet but they normally don't have 2nd teams either so what will they actually enter in a EA league? U11, 12 or something?
And, as far as I know, LAFC So Cal Youth (f/k/a as Real SoCal) is just a normal monetary/jersey affiliation with the standard claim of coaching clinics/training opportunities etc. The Socal Youth players are part of a separate club that does Boys ECNL/ECRL. LAFC could recruit a player from Socal Youth to join their pre-MLS Next league EAL team, but they didn't need the affiliation to do that.