Hi! Thanks for responding and awesome question!
I really like Joan's work, he does fantastic research and amazing reconstructions (I'd love to collaborate with him at some point). I think what he created is certainly valid! In his concept you will see she has on an Egyptian Isis wrap and Hellenistic Jewelry with Egyptian influence. He is basing his (and I am as well) on sculptures that have been found that are highly suspect and agreed that they are portrayals of Cleopatra. I am approaching her ethnicity a little different in that I am heavily basing it off of a particular bust of Cleopatra, though altering as needed to make it realistic. It's tricky work since the busts are already stylized and if it was sculpted by a Roman, they could have put themselves in their work (we all do it). The red hair is a possibility and I will be toying with how to work that in in a way that fits within Macedonian Greek heritage.
My top concept (still work in progress) is 100% Ptolemaic Greek from hair to garments. The jewelry is just blocked in, but I will be pulling from some hellenistic finds close to Cleopatra's lifetime.
My more Egyptian looking concept shows her in her Isis Priestess outfit that she was known to wear. This we actually have identified sculptural reference to go off of, but it is probably ceremonial garment and not worn everyday (particularly the wig and crown).
She was culturally mostly Hellenistic Greek, though she was the first in her dynasty to start to connect to the culture of her people - the Egyptians. It should be noted that Hellenistic Greek material culture had spread all throughout the East, including Egypt (not completely, but it was well established) and it would not have looked like the Egypt you think of when you think of the Old, Middle or New Kingdom.
One of the things I'm fascinated with is when these cultures collide, and Cleopatra is certainly at the heart of the Egyptian, Greek and Roman worlds.
Thanks for commenting!