Long-time backpacker, soon to be first-time mountain climber. Next June, I'm going with a guided group on a three-day Rainier climb. The outfitter has a pretty extensive list of required gear. Some of my backpacking equipment fits the bill. Other requirements elude my expertise, so I'm hoping to tap into your collective knowledge.
(1) Gaiters. For years, I've tromped through dirt, mud, rocks, sand and snow. And never once have I donned a pair of gaiters. The outfitter requires that they end right above the knee, so the ankle-version won't do. What should I be looking for in these? What are some of the lighter options?
(2) Backpack. Right now, my go-to pack is a ZPacks Cuben fiber Blast 2600. The outfitter suggests we should expect loads from 35 to 40 pounds, so the Blast isn't going to cut it. I was thinking of getting the ULA Catalyst. Any other options I should consider?
(3) Sleeping Bag. The warmest bag I have now keeps me warm to slightly below freezing, and a bag of 0-15 F is recommended for the trip. I was thinking about the Western Mountaineering Versalite (10F) or the Marmot Plasma (15F). Any other thoughts?
(4) Gloves. One of the pair of gloves the outfitter requires is a mid-weight glove. They state: "These do not have to be heavily insulated. It is nice is they are wind-resistant or wind-proof. A soft-shell glove works great. You will wear these gloves while climbing at higher elevations." I rarely hike when gloves are necessary, and when I do, I just put on my BPL possum down gloves. So what should I look for here? Are there reasonably light offerings?
Thanks for any help you can offer.

