I wouldn't start off with those boots. GTX = gore-tex = hot feet = blisters. This is a particular problem in desert. (I find after several days of desert hiking I need to get my shoes wet to rinse off the salt build-up.) Those boots won't be a bad choice for the high sierras. Assuming a normal snow year, you'll be walking on snow. Having a bit more warmth and sturdiness (for kicking steps in the snow) is a good thing. The high sierras start around mile 700, so most shoes would be completely worn out by that point.

I would start out with a foam pad Not as comfortable as those big inflatables, but much cheaper and impervious to damage. The length doesn't need to be from head to toe, because your head will be on some kind of pillow-- just measure from shoulders to knees. So the small is big enough for most people. If you do get a thick inflatable, get full length because the extra thickness makes the dangle to floor uncomfortable. A foam pad will lose half it's thickness and some warmth after a month. You can either ride it out with this half pad, spring for a new one, or switch up to the more expensive inflatables.

Finally, down is king when getting a sleeping bag. It is more expensive and getting more expensive. This is the perfect bag for the PCT (assuming you are a guy with a normal cold tolerance.) You could find some synthetic bag that is quite a bit cheaper, but it will weigh more, take up more space, and have a shorter lifespan.

As for a tent, I can recommend the Big Agnes Fly Creek UL 1 with no reservations. I would also check the tarp selection to save some weight and money. A full coverage tarp like this or this would work great. Something like this might work. Some people use simple flat tarps. This would save both weight and money. It seems skimpy to me in a rain storm, so I wouldn't give them an unconditional reservation.