I did the Wonderland in 2013, also in August.
First thing I’d note is that there don’t seem to be any cooking/food items on here, which I’m guessing was just forgotten (or maybe is being carried in the other pack).
Second, I’m not a huge fan of umbrellas. I’ve just never felt like the coverage was that effective in a bad storm. Plenty of people love them and don’t die.
As far as sleeping stuff goes, I did that hike with a WM Summerlite (which is theoretically rated to 32*, which I don’t buy since it’s a mummy bag with only 9oz of fill), and a Thermarest Prolite Plus (R 3.4), so the general temp specs of what I took were somewhat similar to your kit, albeit coming from different items. I was fine in the Summerlite, but chilly most nights. The nights were probably pretty consistently in the low 40s for me (I found the WT very hard to get beta on for what to expect for nighttime temps compared to, say, the JMT, so your experience may vary.)
Considering that I’d probably expect the EE to be a more realistic temp rating than the Summerlite I used, I’d say that I’d probably have been fine for the temps I encountered on my trip. I was plenty warm on the Prolite Plus pad, so I’d assume that, at R3.2, you’d also be fine. I tend to be a very cold sleeper (awful leg circulation) until I get myself on longer trips and can get the metabolism cranking a bit more.
Finally, as far as the tent goes, I certainly wouldn’t be worrying about the weight. That said, if things start to get damp, I’d recommend being very careful with how you pack it up in the morning. I found the sandy volcanic soil do an amazing job at collecting on my damp tent, and it went from being dirty to being a problem in the span of a few days. (My experience with this was one of the things that turned me off of the single-piece tent designs.) You’ll be hiking with a partner, so you’ll have an easier time with this, but I’ve never had a shelter pick up so much crap on it as I did on the WT.
The Wonderland hike is really fantastic- you’ll be in for a treat.