Water availability shouldn't be too big a concern yet. No matter which lean-to site you pick (including WJ), there is available water nearby. Seems to me that as long as you stay low enough (elevation wise) to still have decent tributaries flowing, they're not gonna be frozen over (you might have to bust through a small layer of ice though). It's running water, so it takes quite a bit to freeze all the way through. As far as JLB, definatly water, JB flows year round I beleive, you just have chip your way down to it in deep winter. When all else fails, melt snow.
I've not been up in about a month, but sounds (from trip reports) that it's pretty much winter conditions now. As far a which routes are dangerous, if your properly outfitted for winter (crampons should be manditory now), none of the traditional routes should be overly dangerous.
If it's icy (and it probably is), take particular caution on some of the open rock faces found along the range, such as the east/west sides of gothics, west side of saddleback, upper cone of basin, etc. Without crampons, those places will be like vertical ice rinks if it's icy.
Let us know how it goes.
