Definitely needed crampons/ice axe for the chute and getting up to trail camp. Snowshoes could have been useful, but I didn't want to carry the extra weight. My pack was 13 lbs, brought along roughly 3000 calories.
If you think you'll be fast, 2-3L is enough water; if you think you'll be slow like we were, probably 4-5L will do for the day. A fast pace is like 5-7 hours to summit from whitney portal. We took 12 hours. The last water is at/near mirror lake. When you approach the lake, you'll pass by a stream where you can filter water from.
There is snow starting at 9000', all snow at 10000', definitely need crampons and ice axe. Theres a lot of false tracks in the snow, so make sure you bring a GPS. It's VERY easy to get off trail, especially in the dark because of the alpine start. We had a gps and guided a lot of people who were lost/off trail.
It's easy to also run out of water at the summit; I brought a MSR pocket rocket/fuel/etc to melt snow in case and i used it.
After you reach trail crest, you think you've done most of it, but getting to the summit can be at least another 1-2 hours. The snowfield at the top gets quite slushy later in the day.
There were no switchbacks when we did it, we just went straight up the chute. The chute gets icy starting at around 3, 3:30pm, and gets painful to glissade down. Turn around from the summit by 1-2pm at the latest, suggested 12-1pm to reach trail crest by 3. You definitely need the ice axe for glissading down.
