Sounds like the beginnings of a good trip. I've never been up Silvertip myself, but that's a beautiful area and you'd be sure to see great stuff from the top.
"Normal" Bob weather around the July-August mark should be pretty good. Could be sunny and 85, could be rainy and 45 and foggy, might even snow a bit (but probably not). Good chance of finding mosquitos in boggy places. So, rain gear, sun gear, and a warm layer.
Definitely bring your fly rod, especially if you'll be in the South Fork drainage.
I don't know anyone who carries a bear can. I'm sure some do, but all the local backpackers I know hang food. Montana bears have enough to eat, so they don't try too hard to get human food. Just fry that fish well away from camp and you'll be fine.