Listen, I get your frustration about the misfire at start up. Mine does it and while I’d rather it didn’t, it doesn’t bother me as much as it bothers you. I worked on trucks for 12 years and I’ve trawled many troublesome engine faults. Mine is booked in to investigate. The reason it doesn’t bother me is that as soon as it runs on 4 cylinders it is fine. You tested a second vehicle and thought it was better. I had another 2017 and it didn’t make this noise and although I can’t be sure, it might have run smoother like you thought. I think it might be air that accumulates overnight in the common rail and that’s why it clears so quickly.
Now regarding point 5, you’re way off mark on that. The CX-5 has been meeting Euro VI for several years. There is very little difference between the 2015 model and the 2018. The blank next to the filler cap was always intended for Adblue because it needs it to meet Californian regulations, it is not a devious change that you seem to think it is.
Anyway, I hope they sort it out for you, if my dealer sorts mine I’ll let you know straight away. Don’t let it consume you, it doesn’t matter that much.