Thanks for the instructions! Between these and the ones on ECS Tuning's
website, I knocked the job out in around an hour, including the 10 minutes I sat fretting and referring back to this thread when I was worried I was pulling too hard on the front dome console. I wasn't, and it eventually popped loose.
I got the lights for $14.50 on eBay and all worked great. Only issue is that my footwell lights (2014 535d) are different than the ones shown in this thread and the ones that came in the kit. Mine are already LEDs, but a tape-style bulb (see pics). I need to find a couple of these bulbs, but for now I've just removed them so all the remaining lights are blue LEDs. I also took this opportunity to swap my puddle/courtesy lights with Wind & Fire BMW emblem lights I picked up on Amazon for $30. Overall, I'm very happy with the way it turned out!