… As for "family celebration", I also take it with a grain of salt. Maybe they meant "father, mother and maternal grandmother" in this family celebration. The Queen, however, celebrates the birth of her great-grandchildren issuing a note that says she is delighted with the birth. Sorry, but that is how it is.
Sure, that's what we might know publicly. There's no way for any of us to truly know everything that goes on privately behind-the-scenes. There is ample evidence and knowledge, however, of the fact that Queen Elizabeth is very fond of her grandson, Harry, although her very favorite grandchild is said to be Peter Phillips.
It would be rather ghastly to never be able to let down one's guard among family members, or to have to always behave primly, properly, and formally. As the years have passed, surely the Queen is much more relaxed and informal in one-on-ones with her closest family members. The Queen's appearance with Harry in the Invictus promo video with the Obamas is one indication of the Queen's more relaxed approach these days. Her Majesty's James Bond cameo for the London Olympics is indeed another example of her lightheartedness and her delightful sense of humor. The Queen is extraordinary for her ability to adapt, and for her willingness to lead with a soft touch.
Michelle Obama gave examples in her recent memoir of the Queen's humanity and her straightforward ease in foregoing strict adherence to stuffy protocol policed by royal courtiers.
IMO, there's every reason to believe that the Queen sometimes receives and visits her grandchildren informally. Certainly, the royals attend church privately at chapels inside the palaces. So the royals do see each other on many occasions that are unannounced and unseen by the public. I even suspect that Meghan may have met with the Queen privately at Windsor Castle, well before the publicly revealed tea at Buckingham Palace in advance of the eventual engagement announcement.
That said, there's no doubt there will be official acknowledgement by the Queen of Baby Sussex's birth both publicly and privately. What likely won't be released to the public in every instance are the private occasions when the Queen may see her latest great-grandchild. Perhaps at some point, another official photo will be released of the Queen surrounded by her youngest grandchildren and her great-grandchildren.
https://i.pinimg.com/736x/95/1a/2b/951a2bd2cf98f71315787e1e74634dce.jpg (Peter Phillips was obviously unable to be present on this occasion)
https://nationalpostcom.files.wordp...birthday.jpg?quality=65&strip=all&w=940&h=705
The above past photo is now missing the newest babies, Louis, Lena, and soon-to-be Sussex newborn. And maybe Eugenie will be the next royal to announce a pregnancy. ?