Assuming McVay is lurking around the organization in some capacity next year, absolutely get KK - just not as an actual play caller. Maybe use him as another consultant or some sort of blended/deluxe version of Jay Gruden & Greg Olson.
Going back to college, KK has a pretty good record for the first 7 games of the season, including a 7-0 streak at the NFL level. Coaching is a 12 month a year thing and those decent starts suggest that KK is doing something right in the off-season. I think he's got something to add to the room and I get the feeling that KK might be one of the few people in the business that McVay might respect and actually listen to. Another voice can't hurt (unless he's a McVay sycophant, which I'm assuming he's not).
The Rams have an annual brain drain and having KK around adds a disposable brain and/or someone to help out in the future. I'm going with the Saban strategy of you can never have too many washout HCs on staff doing something.
Save a seat for him in the car, just don't let him drive. If he somehow gets to the wheel, make sure it's one of those driver's ed cars with the second steering wheel and brake pedal on the passenger side, manned by McVay.
