I've heard the Ramona stories too. I'm not happy at all.
I'm not that surprised though, Carole is good friends with Andy - apparently it's the only reason she's back - and Ramona & Sonja had a fall out with Carole over Carole faking Bravo blog comments to appear more popular. That whole situation led to the Bravoholic shutdown and someone at Bravo getting fired, for going after Carole - I was surprised it wasn't mentioned on the reunion. It's the whole Bethenny situation all over again. Andy letting his personal relationships and loyalty influence the direction of the show.
IF it is true that Ramona got demoted, they should do an entire recast and try start a fresh. It's not like it could get much worse with the new rumoured cast. If Andy goes ahead with Carole, Heather, Kristen, & Sonja then I hope he gets fried before he ruins another franchise.
Regarding Aviva, the few stories I've read seem to suggest that she quit. She's filming a spinoff with her Dad for another network so it's entirely plausible.
More Miami rumours are out. They still don't seem to have filmed though. Joanna rubbished the rumour of her coming back but Lisa tweeted "patience" & Alexia confirmed months ago she'd be back and filming in the fall. I have to say that I was hoping for Adriana, Joanna, Alexia, Karent, Ana, and a new wive or Adriana, Jonna and 3/4 new wives. I can't deal with another season of Lea & Lisa.
Alexia and Marysol will be appearing on an episode of Millionaire Matchmaker so they will most likely be back in some role. MM seems like it could be on it's way out though so I don't know if throwing housewives on it is an attempt by Bravo to revive it.