This list looks pretty good to me overall, but as an earlier poster mentioned, the weight is seriously impacted by adding in crampons and ice axe. What sort of crampons? What axe?
You say you plan to start from Waterton in mid-June. I started mid-June (a few days earlier) in 2011. 2011 was perhaps a bigger snow year (?), but no one was starting from Waterton; the normal SOBO start is from Chief Mountain. Check out Yogi if you already have that guide.
Maps, guidebook stuff: what's "Beacon guide" ? You don't list either Wolf or Ley. Bear Creek maps are great, but I'd still take Ley — Bear Creek build in the fiction that's there's just "one" CDT. Ley recognizes that it's just lots of alternate routes stitched together. And includes margin notes. Bear Creek is easier to read, but if you take just one, take Ley. Optionally print on larger than 8-1/2 x 11 paper (11 x 17 if printing cost isn't too high for you that way). Wolf — I could see leaving Wolf off. Lots of detail, interesting stuff, and once in a great while helpful navigation stuff.
Indeed the weight of paper you're carrying is significant. I think I ended up going with 7 resupply boxes rather than my original plan of 6, in part just to split up all the paper weight a bit better.
In a normal snow year you'll spend more time in snow in Montana as a SOBO than you have on likely any other trail. Doesn't mean you need more clothing than you have, but indeed in Montana and Wyoming you can get fierce hail and rainstorms, which often don't last too long. I personally wouldn't inclined to an umbrella, but I'm a two-stick hiker.
Check with Glacier to see when they put the bridge decking in place. If it means shifting your start date just a day or two, consider that to wait until they have the decking in place. Crossing some of these creeks were by far the fiercest and most dangerous creek crossings I've ever done.
Bear line: my hiking partner and I were forced to borrow bear cans in Glacier. I bought some cord before walking into Yosemite just to follow their rules, but otherwise never used bear line, FWIW. OTOH, I did carry bear spray. Up to you if you want it or not, but I would do that again — grizzlies are different than black bears. We ran into a couple of goat kills that made us hustle along. Only one real grizzly confrontation, but it was memorable.
HOW long do you think your longest food carry will be? And perhaps in a lot of snow? Not clear on your plan there. I had a couple of 8 day carries; going into the Winds I pulled a muscle in my back carrying 8 days of food to start, and that took a while to get pain free afterwards.
No gps, or cell phone as gps? If you can get Ley data on your phone, I suggest that as a backup to map & compass. This trail is rightly reputed to offer navigation challenges. Some do succeed with just map and compass, but if you're out there by yourself, you don't want to get that wrong. Coming out of Colorado I had a day of sleet and snow and very low visibility, with new snow covering track markings. I was very glad to follow GPS guidance in near white-out conditions.
Best wishes for an excellent trip!