Maybe yes, maybe no. Definitely don't expect it. Being honest....the Pier J is waaayyyyy better for a family. I'm CX DM (Cathay's OWE equivalent), but I go to Pier J about half the time I'm in the Pier area, instead of F. Once you have 4-5 passengers, it becomes even more no-brainer to go to Pier J. Huge, tons of different rooms / unique food areas, and just massive quantities of seating and a lot of different vibes. The F lounge really sucks for families IMO, except to say you're cool and eating in a free mediocre a la carte restaurant or this is the F lounge. Back to my praising of the Pier J lounge, there are day beds in the back, a tea salon, a whole a la carte buffet area, a noodle room, espresso cart, it's good. Pier F self-serve food options just completely suck. It's this tiny "pantry" concept that looks aesthetically pleasing and is quite useless based on what they normally stock in there. J self-serve food absolutely blows F away not even close. So the problem with F is, unless you're sitting down at that (mediocre) restaurant, you really don't have good food options at all. And no I don't always want to eat at a damn restaurant, especially one that frequently mixes up my order, can't always be relied upon for speed, and honestly doesn't have that great of food compared to what I can eat in town an hour before.

I really don't think I'm going out on a limb and saying Pier J is hands down the best option for a family of 5. I often choose it as my own option as a party of ONE, and its utility only goes up with a group.

I think Pier J is arguably the best lounge in HKG, including over the F lounges.

Oh, and if you're into wine, it's not like Pier F offers anything much better. If you're serious about wine CX has atrocious offerings in both lounges. But the hard products are stunning - I'd go so far to say that Pier J is possibly the best J lounge in the world, at least in the very top echelon. Absolutely better than scores of F lounges.

Switching mid-flight is not allowed. You are allowed to swap the passengers at boarding (against what name is on the seat), but you can't let someone have F half the flight, and someone else have it the other half.

If you're just talking about different flights...aka mom/dad take it this flight, kids take it next flight (regardless of whose names on BP), that's not a problem.

Also not allowed. The people sitting in F can use it, but people from J and Y are not permitted in.

There are many threads about it. I've seen this a lot, and it's denied almost every time. I have seen a few exceptions but they're very rare.

The most normal "exception" is if a kid is in the back, and two parents are in front and there's an empty F seat. They'll usually let the kid sit in F for landing so they can be together to deplane and catch their connection. That's about the only normal exception I see.

Seen more rejections than I can count. Otherwise, you'd have people buying 1 F seat and just hosting parties. That's not the spirit of it.