I've worked more on the CXV than I have the launch vehicle, so you're starting to get out of my depth a bit. Technical details like weights and propellant loads are, as far as I know, not generally broadcast to the public for competition reasons, although believe me, NASA has seen a LOT of charts on this. The second stage does not go into orbit. There is quite a bit of propellant on that CXV.

ISS operations are problematical, not technically, but from a standpoint of getting vehicles approved to approach the Space Station closely. Some designers have gotten frustrated enough that they are proposing "parking" their supply vehicles some distance away, and having an approved vehicle, like maybe a Soyuz or something, act as a "taxi" to ferry supplies. I don't know at this stage if t-Space will go that route.

Frankly, most of us are thinking about our own space stations.

0 to 3 gs is not a serious problem, even for trained civilians. However, at launch, the fully-loaded vehicle will not immediately see these loads.