Came back from Shasta last weekend.
Went up Avalanche Gulch. Camped at Helen Lake. Definitely don't need snowshoes beyond Helen Lake. It's a personal choice for snowshoes below Helen Lake. We went through the trees as much as we could on the way up and didn't really posthole that much. On the way down after a day of sun, there was a lot of postholing (the glissading was all the more fun because of the soft snow). Route under the Thumb was covered with snow and most people were going up that way. There were small rocks that were falling going up from Helen Lake so a helmet would be advisable