No germ issues in a non-shared hone. The hone will dry pretty quickly and you'll be good to go each time you use it.
Don't do anything to the hone to sterilize, you may damage the stone matrix.
Some stones, you can boil without any issues (like oilstones), but I don't know if that extends to the PHIG. There are definitely artifical stones that are OK for a soak, but that come apart with heat.
In terms of the edge, a well settled-in chinese hone should leave an edge just as soft as a coticule but finer. It won't be so soft and fine with a slurry, though, thus my comments above about letting the surface stay polished and settled.
I would peg the cost closer to $40+, as the big hone at woodcraft is well worth having over a smaller hone that's less than the width of a razor blade. It makes honing as you would do it with a very slow cutting PHIG a lot easier, esp if you're doing circles, etc, with moderate pressure - it's really not nice to have the razor going over the edge with any pressure.
Maybe this page was shown a million times before I got here, I don't know (and I don't know or know who the page owner is), but it's instructive about what's going on with different stones. Pay particular attention to the smoothness of the edge in these pictures, more so than attention to the polish on the bevel. The two go together somewhat, but the polish on the bevel isn't what's cutting your hair. You can see how the shaptons polish is great, but there are undulations in the edge, which maybe explains why it can be uncomfortable to shave off of some of the synthetics.
http://www.tzknives.com/razorbevels.html