Can't comment on the west ridge itself (looked like the snowline was down to round hill) but I got over to the waterfall area on Buller yesterday morning. The decent down to the anchors above the waterfall was pretty good with areas of quite soft snow and patchy cover. The waterfall itself is forming up as below.
The left most fall (just to the left side of the rope in the photo) had formed all the way down and was climbable with some delicate moves. The column was still a bit thin though so I only had one lap before retreating. The middle two falls were still hanging while the far right hand end looked fairly good but I didn't go over to have a closer look. The lower slab was very nice.
I thought this was a fairly good score as I didn't expect much to have formed and with a few more cold fronts and sunny days it should be pretty fun up there.