Questions about the Phase Trait

By Crow Eye, in Dark Heresy Rules Questions

So, I was wondering a few things about the Phase Trait. Phase grants both the Incorporeal and the Hoverer traits, which got me thinking about a few things.

If a phased (incorporeal) individual falls from a deathly height, do they impact the ground harmlessly? Given their momentum, would they pass straight into the ground as their merge ability (provided it wasn't warded or shielded in any way)?

As for the Hoverer trait, in a zero-g environment (such as a starship with depowered grav-plates, or even open space), would Hoverer essentially become Flyer, or do they still need an object of mass to hover next to?

Daemons can hurt phased individuals, given incorporeal individuals are partly in the warp, but given daemons are as well, even when manifested, would a phased individual be able to hurt a daemon as well?

Lastly... incorporeal psykers... yea or nay?

Just curious what others think