The women in the hot pink dress is indeed Donata.
I don't now, if Georg's stepfather is guest at the wedding. Until now I always saw Donata walking alone, what makes me believe, he doesn't attend.
There might be two reasons: His stepfather was married first to Georgs aunt Marie Cecilie of Prussia ( so his cousins are also his stepbothers and-sisters). The marriage of Donata and him caused a lot trouble in the prussian family. Georg also never said a word about his stepfather in public. I have heard, that their relationship is not the best.
Second: The man is 75 and may be not in the best physical condition.
The heavy set blond women is the chief of protocol of the prussian house and the head of their house foundation.
The women in the light blue dress is the mother of the bride.
The women in the red flower dress in the tv report might be her sister Isabelle, but I haven't seen her face clearly.
Georg's sister Cornelie is accompained by the brides younger brother Victor.
The women in the lilac dress is her sister archduchess Katharina surrounded by her children.
The man with the dark hair and the pink tie walking out of the door is her brother Alexander.
Her father is the man with the white hair and the nice belly
Here is a better gallery of the legal wedding, where you can see Victor and Cornelie:
http://www.rbb-online.de/fernsehen/projekte/hochzeit/das_brautpaar/die_standesamtliche.html
Georg's grandparents are all dead. You can read about that on preussen.de - aktuelles or geneall.net
His uncles are all not invited. His only living aunt is Marie Cecilie, may be we will see her the next days.