I use MegaScenery Las Vegas with Fsdt's Las Vegas and it works GREAT! Even Aerosoft's Las Vegas added to the mix works very well. I expect Fsdt's LAX will work very well with MegaScenery SoCal!
In my humble opinion,
Same here. I'm using MegaScenery Vegas with FSDT KLAS, MegaSceneryEarth with FSDT KORD and KJFK, and MegaScenery Dallas with FSDT KDFW. No problems with any of them, except MegaSceneryEarth gives me a funny mound at the end of one of the runways at KORD. I am still not sure which part of the MSE .cvx files it is that's causing it though, and to be honest its not a big deal.
I have no doubt that KLAX should work fine with MegaScenery SoCal as long as you have it on a higher scenery layer. If it doesnt' I am sure the guys at FSDT can come up with a solution to make it work should their be any issues.