Reviewing Shofu's youtube playthrough, I actually change my mind, your assumption about Anna being an Elite 4 may be sound. The proof for it could be here [link]
[/link]
Also, Heather being part of the Elite 4 was stated in game to be a possible result of her mother previously being the Elite 4 and the keeper of the Amethyst Pendant
I don't know if this counts, but it applies to most Elite 4 members. Charlotte found the Sapphire Ring when her parents had died, so it's safe to assume one of them was an E4 as well, if we go with the theory that the E4 were the key-keepers.
So up until now, Heather's Laura's and Anna's parents may all be Elite 4, which brings me to my next question, a matter that I think is very important for the story;
Who the f*** is Radomus, in the Reborn site leader page, Anna is indeed listed as a leader and because her team is supposedly made of psychic types, I think we can assume she isn't the champion because Ame wouldnt make the chamption have a monotype team, as that would be too easy. So my theory is as follows; Radomus is related to Anna, could he be her father? I'm only basing this on his interview, but he said he danced on his soulmates soul or something along those lines. Could his soulmate be Anna's mother? As stated in a previous theory, Anna has the power to do the impossible, as does Radomus, now what if she had inherited that power from him ? This is wild speculation here but I'd like to hear your guys' thoughts on the matter
Forgot to mention that he is also the keeper of the Amethyst pendant