Sort of related to your felt on the seat belt thing - 2 Grand Cherokees ago we had a very minor cosmetic issue with the headliner. The vehicle was 3 or 4 months old and the edge of the fabric straight ahead of the passenger, very front edge, was a bit loose - instead of tucked up in and secure, the edge could be seen. The adhesive didn't hold and the edge came out from above. I took it in while having them do some other little thing and (knowing I could fix it myself in 5 minutes but wanted them to do it so if it was messed up, it was on them, not me LOL - wife's vehicle!) I asked them to take some 3M adhesive and just carefully work that edge back up there. It was a whopping 2-3" or so.
Yeah, that could happen especially if the felt piece isn’t available. That could come already applied by the seat belt supplier.
I have ours going in for headliner issue where it's not secured in the middle of the rear panel.
I wonder about electrical editions also, I'm reminded of a man I used to work with who would buy a new Harley and modify it until it was unreliable then blame the bike. There is a lot more electrical than mechanical on these trucks.
You aren't an auto tech obviously. No, misfires are not timing related and spark plugs have nothing to do with it. In fact they'll last tens of thousands of miles.
