I had a 2015 L model, and it also didn't have a key fob. I took the car in for service, and mentioned I would like to have a fob made for the car. My dealer did it, but it will cost somewhere around 100 bucks. I don't know if it was a system they had to install, or if the car might have had one...
I think the high rev issue has something to do with the adaptive cruise control. You can try switching over to the standard cruise control mode by holding the cruise on/off button for about 5 seconds.
It is your engine gearing down while going down a incline. I have the same issue, and if you tap your + paddle on your steering wheel (SE models) it will shift back up. It doesn't have to be in the manual mode for you to use the paddles.