N ice update, KH. Your experience at LAX with MX was similar to mine. Too many helpful staff to direct me to the right counter, etc. Guess I missed the ANA Lounge. Seemed to me like all the open ones were oneworld alliance members the night I passed through. I agree the MX 757s have the best J seats I've experienced in a long while, save for the 763s with CP metal. (Movie on my overnight into MEX was "Ballad of Digger Vance", which has now been playing on just about every flight this past two months! Played on main screen, no personal videos on MX flights for me.)
As for the second A330 J cabin, I was having the same thoughts on my flight between YUL and FRA. We were given the first row in Hospitality, left side and the cabin in front was empty, all the Js being accommodated in the front one. Until the FAs spotted a couple of friends in the back of the plane and invited them into the private enclave for the trip. Maybe AC now has its own version of UA's employee class. Don't think the main J cabin was full Saturday night.