I don't like tying Di's powers to Artie. It contradicts their use in the WML stuff, & implies that either Banas or Amazons other than Di are non-super. My idea for a fix: Artie could have won the Contest if she, & most Amazons, had superhuman speed & strength.
I maintain that Neron is a "New God" who invaded & conquered Hell. His fashion sense gives him away.
I felt at the time that the Polly & Donna continuity of Byrne's final arc was properly transitional, & eventually time would heal into some less head-spinning form. On the other hand, the merry causality-bending can be seen as a tribute to Kanigher's Impossible Family era, & I sort of like the idea of Polly in the 1940's knowing something of the future.