The family probably doesn’t want Halfwit or MeGain at the funeral to pull focus or have some kind of bratty tantrum as they always do. Since the UK still has restrictions on how many people can gather, however many people are allowed to attend a funeral service right now is probably not very high. With all the other family, friends and longtime staff who will attend, the Harkles can easily be left out for COVID restriction reasons.
If there is any limit on mourners at the funeral, I hardly think staff would be allowed before the grandson & his family. If the queen told Harry & Megan not to come, imagine the uproar from the liberal press.
No, Harry will be there, but probably not Meagan. I doubt she will ever visit the British Isles again.