Can not answer yet since these questions are in a lower group of priority compared to the main version even if for the 3 questions, we are closer to being able to make them because of the work we did on Turbo. This being said, the 64 bits is the most likely of the three (by far at this moment)
64 bits support does not mean all integer would go in 64 bits for many reasons, but that we can make use of them or, and it's the main gain, that we can address more memory.