That's it. No busybox, no Superuser.apk installed in /system, no deleting apps that you just assume nobody would ever want, no nothing. Those four files. That's it! How hard is this? Oh, and if an install-recovery.sh script already exists, then rename it to install-recovery-2.sh so it still runs. Don't just overwrite it because you assume nobody in their right mind would want to knowingly keep stock recovery.
When you start deleting stuff off of people's system partition, it makes the probability of failure for future OTA updates very high. This same thing holds true when you install busybox into /system/bin. Don't. Do. That. On that same note, don't install Superuser.apk on the system partition. Let people install it themselves from the Play Store. Just provide that as a step in your instructions. One less thing being added to one's system partition is a good thing. Rooting should be as minimal and non-disruptive as humanly possible. Once those four files are there and permissions are set appropriately, you have root and can do whatever you want.
Let busybox, system app deletions, stock recovery install scripts, etc. all be up to the individual user rather than you trying to impose something on them