Umbrella: I started the PCT with a chrome dome umbrella and didn't use it much. I love the idea, but I use two trekking poles, and despite some cursory attempts I never found a hands-free solution that satisfied me. The other issue was just that sometimes when I most wanted a sun umbrella the wind made it difficult to use. Result was that I mailed it home. If you don't use two trekking poles your experience might be quite different.
Combined trip: seems ambitious to me, but do-able certainly. I started the AT this year in late February and I finished near the end of July, but I took in total about 3 weeks off along the way (over two weeks to deal with a bout of something giardia-like). If nothing forces you to quit or take a break and you're a strong hiker, mid-June should be possible. Far ahead of the norm --- even after three weeks off the trail I was still well ahead of the pack at the end --- but certainly possible.
30-degree bag: maybe someone like Tatu Joe can get by with that sort of bag when it's damned cold out, but not this boy. I suggest that this winter you look for a place you can do a field test of your gear where the overnight temps get down into the mid-teens or so. If you can contemplate doing that for several night, and have temps in the lower 20's quite a few more nights, then okay, with the additional caveat that you'll have to be more sensitive and ready to walk out of danger if really cold temps set in.
Certainly that's going to be an issue in the Sierras and SoCal on the PCT as well. For most of the trip, however, 30F bag is a great choice for both trails IMO.
Torsolight pad likely will hold up for both trips IF you put at least something under it. Consider a 1/8" Gossamer Gear thinlight pad. I've never had an inflatable leak on me, but I always have at least some minimal padding like this underneath, and I sort of automatically pick out and brush off needles or other particulates when I roll up that minimal padding each morning.
Again, however, field test your padding combo down to mid-teens before starting.
Gatewood cape: I actually started the AT with a GC as well as a really light Oware bivy. For this year, at least, starting early going NOBO there were lots of blowdowns, and having not only my only raingear but also my only shelter at risk from going through those made me nervous, such that I ultimately switched to a rainjacket and tent. But perhaps in a more normal year (the south got hammered more than usual last year) it wouldn't be a problem.
In which case I think it's a great combo, as you'll almost always find shelter space if you start early and hike fast. I.e., a minimal tent option is a great choice then.
Would you add the SMD bug tent when appropriate? Or just a head net? Between the two trails you're bound to find some buggy times, perhaps not until the PCT however, given your schedule.
I used a montbell thermawrap vest and like it; on the AT I actually wore it while walking a few times, combined with a windshirt, normally too warm, but a nice layer to add sometimes, and bounce or mail home when it's warmer.
I combined that with an alpine light parka in a 20F bag on the AT, and that worked for me, along with down booties.
Backpack: remember that you need to be able to carry a bear can in the Sierras. And note also that if using a poncho that you might have an ice axe strapped to your pack.
Droid X phone: serendipitously, I just bought this same phone myself. Not sure what mapping software I'll put on it yet; it's actually backup, as I'm going for the CDT next year and will reluctantly carry a separate, standalone GPS. You definitely should not, however (!). Anyway, my conclusion too is that the Droid X is a nice choice, and it fits nicely in a snack-sized ziplock, and the touch screen works decently inside the ziplock. Voila, waterproof. Have to take it out to use as a camera, however ...
You're biting off a lot, but with the right prep, and if you're reasonably strong and fit when you start, it's certainly possible, and a heck of a journey. Best of luck!