The Solstice is still in the construction stage - it's inaugural sailing is Nov 23. It is due to start its sea trials tomorrow - (sept 28).
Until then, nobody will be able to answer your questions - except from info that Celebrity has distributed. Once the first reports from that Nov 23 sailing come out, you should have all your questions answered.
Millennium-Transatlantic-9/01, 10/03, 11/05
Zenith-Special Caribbean 11/06
Back to back Millennium 28 days - Mediterranean 11/18/07, Transatlantic - 12/2/07