You've replaced a lot of your front components but did not tell us if you have lifted your truck.
You are dealing with a dealer, how recently did you get the WJ? Like all vendors, be careful, just because they're a dealer doesn't necessarily mean they honorable and stand by their work. If you need a mechanics help, seek out a 2nd, 3rd, 4th opinion. Any mechanic worth their weight would not turn away a customer who comes in, describes and issue, shows some concerning things, and asks for their opinion on what could be the cause. Once you've done this, go back to the dealer and call them to task and see if they will honor their work as it sounds like something went wrong after they did something.
Your vibrations could be caused by an inproperly balanced wheel, or one that lost some of it's weights. Alignment issues can cause rubber breakdown like you have in your pictures, especially if tires have never been rotated. Buy a tread depth guage, or borrow one, and see if you still have at least 4/32nds of tread depth left. If you don't, or you are close to 4/32nds, it's time for new tires.
Your friend is right, our WJ's need four matching tires. Same make model and pattern, as patterns on some tires do change over time, and on top of it they should have within 3/32nds of treadwear between each other. If possible, have 5 matching tires bought all at the same time and follow a 5 tire rotation pattern regularily. Most people go with 4 and a whatever 5th, which you can get away with for very short distances, but I had to get my transfercase rebuilt after having to driving 200 miles back to civilization on a mismatched spare as well. Believe me, if you grenade your TC like I did you'll wish you dropped the coin on a set of 5 matching tires. Your fuel economy goes down the crapper and the cost to have the transfer case repaired is well more than a set of 5 matching new tires.
If odd wear is only on the one tire, you could have a bent axleshaft or perhaps the wheel was not bolted back on properly. Have someone drive it while you follow looking for wobble in any of the wheels.
Possible red herring: Your symptom of vibrations only during decelleration sounds exactly like my current issue (front driveshaft) before the vibrations became more often but still mostly or worse during decelleration. The cause for me was a dying front driveshaft but this similarity could just be a coincidence. If this is you problem, it could be an issue with bearigns, yokes, or a bend driveshaft alltogeather.
Finally, when it comes to fixing things. Search online for aftermarket parts. Typically they're WAY cheaper and usually you can upgrade stock compentents while saving money doing so. For example, the vendor who goes by the name of Kolak on this forum is awesome to deal with and has great pricing.