One of these new APS-C E-mount cameras will have a great feature: You will be able to use Canon and Nikon mount lenses on it simply with an adapter. Also there will be another great feature can make you happy, and the price is not very expensive.
About Sony NEX-FF: the release date is not yet confirmed, maybe late 2013 to early 2014, previous rumors said it will be announced on September 24.
About Sony NEX-7 successor: There will be a big firmware update on NEX-7 after September new product announcements. And NEX-7 successor release date and price is not confirmed yet.