There's no zero-G going on here. They experience the same gravity as you are sitting in front of your keyboard (well mostly - at least 99% of it). They are however in free-fall which results in weightlessness.

There is no known technology that can recover data that has been overwritten once on current hard drive technologies. The original recovery research was done on drives prevalent in the early 90s using Magnetic Force Microscopes (MFM). The track density of modern drives is far beyond what would be required to reliably (or even statistically) read data that has been properly overwritten. The DOD still requires 7 passes, but there is nothing in the public literature to suggest that anything more than 1 pass on current disk technologies is required or useful.