Desolation should be open, just to June rather than typical July conditions. I'd expect all trails to be clear by now. I was on Ralston Peak two weekends ago and there were still big snowfields on north-facing slopes, but it's been quite hot since then.
Wildflowers should be great, and that generally means lots of mosquitoes too. Nevertheless I'm headed back up there this weekend.
I'll defer to others on Yosemite.