Yeah this might be where we agree to build parallel elseworlds. I'm pretty hardheaded at this point in that I prefer the demigoddess Diana retcon and the artifact-armored Cassandra reimagining. I do think your other ideas are great though. I'd give her a sword and shield, but I think her actual weapon should be a mysterious bow that fires thunderbolts.
If Cass is going to have a friendship/mentorship with an Olympian, I'd prefer Hephaestus. He's the origin of all her toys, and he should teach her how to make her own.
Obviously, Julia Sandsmark would be a global archaeologist, so Cassandra would end up with Norse, Egyptian, Yoruban, Chinese, Hindu artifacts available to her, with all the proper global adventures that would be appropriate.
How important is it to you that Cassandra is blond?