You will definitely have bugs. My strategy for avoiding bugs in the early season is to camp and take my breaks at elevation as much as possible. High exposed areas tend to attract fewer bugs, both because they are colder and because of the wind. Definitely avoid stopping/camping in areas in the trees and near mosquito-breeding bodies of water. And take DEET. Lots of DEET.
As far as snow goes, as suggested above, check out trail reports closer to your start date. If you monitor trailjournals and the PCT-L forum, you might be able to get an idea from some of the early PCT hikers as well. By the time you get there, you should not be breaking new trail in the snow – there should be a number of PCT hikers through the area by then – but it still could be slow and difficult. Some of the crossings may be challenging as well.
For an idea of what it will be like, you should check out prior JMT journals of hikers who went at that time of year, or PCT journals of hikers who passed through the Sierra at that time. Each year is different, so it is hard to say what this year will bring, but if you read journals for a few different years, it should give you an idea of the range.
Kanga