I'll answer as many questions as I can from my own experiences:
1. The image sizes are given in Megabytes, although they are approximations. Actual image size varies with the range of tonal and colour variation in each image. The buffer size is tricky to calculate precisely as the camera is writing to the buffer at the same time as the buffer is writing to the card.
2. From my own experiments, buffer flush speed is about 25 MB/s. 10 frames written from buffer to card in about 8 seconds.
3. The camera can only write to the card as fast as the buffer allows - 95 MB/s cards have little margin over 45 MB/s cards, so the buffer write speed is the limiting factor. Where the ultra-fast cards do gain is in reading to a computer via a USB or e-SATA card reader. The high read speeds reduce copying time.
4. I'll leave that to the original author.
5. Yes, it does, but it fills faster than it can empty.
6. My own experiments yielded a result of about 11-12 frames. 10 frames fill the buffer in about 1 2/3 seconds, but nearly two frames can be written out in that time, so about 12 frames before fill rate falls to write rate which is 2 seconds at 6 fps.