JM, that is the most organized garage I've seen in a long time... talking about my Dad's... I try, but nothing like his or yours... very nice!
like the custom shelving
Check your owner's manual. If you don't have a copy you can probably find it on the manufacturer's website.
A 50 or 60 pound kayak will have different requirements than a 140 pound yak. If you use a hoist make sure the system is designed for your weight requirements. A new Hobie PA14 with seat and drive weight 148.5 pounds with nothing else in the boat.
For hanging our kayaks, I bought bicycle hoists. The hooks that hook under the seat and on the handlebars of a bicycle hook perfectly on the handles on the ends of the kayak. Toss your paddles, life jacket, etc. inside the kayak, hook the hoist ropes to each end and they lift right tight to the ceiling! If you don't have handles, tie a 4-6" loop of rope and hook it on that. I have 9' ceilings, so this would be a pain without this system. It would require a step ladder and two people. You can customize the spacing of the pulleys by spanning the trusses with a piece of 2x4. My wife is 5'2" and 110# and has no problem hanging our kayaks by herself from the safety of the concrete floor. The best part? The kits are $10 at Menards! I have an Old Town Guide 119 solo canoe as well, which I purchased the actual kayak hoist for since that weighs a little more than the kayaks do. It works great as well!
I just use these straps cheap and effective. Just carry your kayak up to them and slide them thru the 2 straps as they hang from a ceiling joist. When kayak is in place you cinch it all up to the ceiling. I do have to use a step ladder to pull on straps and get kayak all the way up to ceiling and down again
I dont see why you need lumber and carpet. That will make for a heavier load