1. You never need to do a backup, it's just recommended.
2. I would recommend OTA Rootkeeper whenever you upgrade OTA. It has a temp unroot/protect root option that should let you retain root through and OTA. As long as you don't make any changes to the default system/apps. You said be able to unroot and take OTA without issues.
Hope that helped clear up your questions.
Sent from RAZR Maxx FlyingJelly
Looking into OTA Rootkeeper I noticed it said it might have a conflict with SuperSU because it has it's own rootkeeper in the pro version. I don't have the pro version, so should there be a conflict. I installed Rootkeeper and under status it has the Google Play button for the superuser app installed, so I'm assuming it doesn't even know SuperSU is there. All the other boxes were checked and It still let me protect the su, but will this be a problem when the OTA comes?