No it's not.
Check your app list and see if it installed a second app somehow. You should never use these types of apps. They are nothing but snake oil.
Your camera may have been activated on accident while in your pocket. It has happened to me a few times.
Glad I could help. Their are several good launchers out their. I prefer Nova myself. With Nova Prime (the paid version) you can get unread count...
Yes, you didn't have anything on it besides the OS and pre installed bloatware so it wouldn't take long at all.