Shocks aren't supposed to support the weight of the truck, so if it's sagging that much, you probably need new springs too. If you jump on the back of the truck, once you jump off, it should immediately recenter and stop. If it continues to bounce around, the shocks are blown. If you can move the shocks easily with your hands when you get them off, they're blown.
I bought my truck about 10 years ago with 130k miles. The shocks failed pretty quickly. The springs seemed ok, but I installed 2 inch lift springs from A/C Customizers anyway. If I could do it over, I'd probably have used OME lift springs because I understand they are a little softer. It rides a little rough now, but it handles much better. At that time I bought some Rancho shocks that A/C Customizers said were factory fit. They weren't, but I made them work, and they are going strong today at 250k miles, so can't really advise on shocks. You don't need extended length shocks though, especially if you don't extend your rear brake lines.
Your first 4wd SUV brake job will be a long and messy job compared to a passenger car. But it is entirely doable if you accept it as a learning opportunity, go slow, and use the factory service manual. I haven't used the brands you are considering. Though my ceramic pads may have been Centric.
I replaced my front brake pads with ceramic about 3 years ago I think, that I bought pre-emptively about 8 years ago. I used Autozone mid-grade brake rotors. Within a year they had developed brake jidder. After research I don't really blame the rotors. I think I didn't pre-clean them thoroughly enough, and I may have pressed on the brake after some high speed hot stops, which is a no-no. I replaced them with NAPA's store brand high grade rotors, and cleaned the hell out of them with soap and water, and then degreaser, and was very careful to not contaminate them with grease when re-installing. So far, so good.
Hub/wheel bearing replacement is overkill if you are able to set the pre-load correctly and don't find evidence of a spun bearing when you are in there after cleaning everything up initially. I did replace the grease seals, and used synthetic grease in one of those bearing greasing cups that pushes clean grease thoroughly through the bearing.
You'll need to buy the bearing socket, or get the Ford 4 prong socket and grind off 2 of the prongs, and shape the other 2 tongs down to work on the Pathfinder.
Some people also completely wing the pre-load process. I half did. I used my regular torque wrench to tighten the bearing nut down to the spec (which is very high), rotated the hub as you are supposed to, backed off the nut until it was free, and then I didn't have a torque wrench that had a low enough range to set the final pre-load. If you want to do it right, you need one that goes down to about 10 inch pounds. In the end I did it by feel. Then if you want to be able to validate you got it right, you should buy a fish scale so you can use it to measure the brake force to start the hub turning.