I agree with previous posters, it wouldn't be fair on other pax and on the staff -- Thai culture generally is one where people don't want to say "no" (even if it is the right thing to do).

To be fair to the staff and your fellow pax, I would advise following Thai-Kiwi's policy --> inform the cabin crew that your children are in Y and that you'll visit them and not vice versa. It isn't fair to put the decision on them or your fellow pax.

Enjoy your trip in F with your wife, focus on the whole holiday for the kids (I am sure the are very excited about visiting Thailand !!!)