Welcome to the board! I'm also getting back into it - still. Over the past two years I have dayhiked myself silly and slowly worked over my gear list. Normal pack weight is a compromise between what you feel safe taking, and what is lightest. (and what fits your budget!)

The sleeping bags are heavy for the temp range. You should probably look into something 30F or lower for high elevation Sierras, or figure out how to augment the bag with an overbag or layers of clothing. Of course, if 90% of the time you are going to places where night temps don't drop to 30 or below, you may want to rent bags or borrow for when you do head for higher elevations. Some folks get a second bag to take in more extreme cold. Temps in Yosemite do vary a lot - we stayed a night in the valley and were comfy at 50-55F then hiked to Little Yosemite Valley (not that much elevation gain) and found ourselves sleeping in 35-40F temps. I was fine, my down quilts are rated to 25F, but others were not so prepared and I think someone actually resorted to sleeping in one of the pit toilet stalls. I have heard that it's 10 degrees for every 1000 feet of elevation gain, but the Sierras have their own weather and it's best to be prepared. 30F minimum is what I would take in summer.

Pack will need to be what fits you and what works for your gear. Most here will say that you figure out the gear, then your pack. I agree - I sold a few packs before I was through. My current gear list vacillates between 50-60 liters, and usually weighs 25-29 lbs inclusive of water. I found two packs that work for me, an ultralight Gossamer Gear Mariposa Plus and a Granite Gear Nimbus Ozone, both of which have swappable hip belts as my hip belt size is different than my pack size. When I need a bear canister or want to take the bulkier synthetic quilt I take the Ozone. You will need to consider the bear canister for trips to Yosemite, by the way. It's mandatory there, and you have to choose from the SIBBG approved list.

If you're looking to lighten your load you may want to research tarptents - some nice 2 person ones available.

I've been wearing Salomon trail shoes and Keen mid height boots, neither one is heavy duty. If you are hiking on trails and not doing "rough stuff" light duty hiking boots are fine. I have found that rattlers tend to be gone; guess I'm a noisy hiker, plus I have trekking poles to push away the unwanted dog or snake. I personally have never used goretex and prefer to have breathable shoes that dry quickly. All my hiking is either in the Sierras or in california coastal ranges. YMMV.