Update: Switched things up a bit.
Now doing four days in OC, and the final three in Malibu.
We've done all sorts of things up there, mainly beach strolls and parties and picnics - San Petro, El Matador, they're all just so great - but my kids have never stayed up there.

So, first four nights at RC LN in an ocean view suite. Wanted Montage but base rates started at $1600. I've stayed there and, even if the whole place was just fully re-built in the exact style it was before, with same amenities/service, just not worth it to me.
From what i remember of an erstwhile long weekend there.
Ritz base was about 9 bills, still eye-opening but the step-up to relatively large-looking suites there was not as sharply angled.

Malibu Beach Inn - two separate rooms - for final three nights, after a quick stop on the way thru L.A. Tried first for Nobu Ryokan, have seen a room there and the place looks incredible, but it's booked. Perpetually booked, actually, I've tried before. I'm sure the right TA might get me in, but moved on.
Malibu Beach Inn has gotten near-rave reviews from friends who've stayed there, as well as a strong thumbs-up from JGHassell elsewhere in this sub.

Not sure if either of these properties will compute as 'luxury' here. I have slightly higher hopes for Malibu Beach Inn (far smaller key count, it's a LHW member, not part of a corporate chain, etc), but if either of them impress greatly I'll for sure attempt review(s) here.

Rancho Valencia continues to be on my list. Beach Village at Del Mar has been added to my interest list. That Alila looks quite spiffy too, location seems perfect.
Thanks as always folks!