LR 6 has improvements in de-mosaicing x-trans files.
If you are are actually going to use Photoshop, then the CC photographic suite has a great price point. You can always run the latest raw converter to convert into DNG and go from there, but you lose a lot of convenience by doing this.
X-Pro2 is only supported by the latest Lightroom release and yes, it is already supported.
I'm running one installation of CC (LR + PS) on two machines and a standard license LR 6.4 on two more machines. But I don't own an X-Pro2, "only" X-E2, X-T1 and X100T.