@Paul Lee Excellent configuration! Avast Free AV is a great free AV when compared to all of the other free AVs out there for protection.
Looking through your security config I cannot see anything that I would add other than having a system image backup. You have everything pretty well covered. I think Malwarebytes wouldn't be considered a System Utility.
A system image backup that I would recommend anyone to use is Aomei Backupper Standard (free) and Macrium Reflect (free). Both of these pieces of software are tried and true methods of creating a system image backup. It is best to have system images in case something bad happens to your OS, but I'm happy to see you are doing data backups on a weekly basis. This is critical!
Having an external HDD that is 1 TB is great. Just be sure to not have this connected to your network or directly to your computer all the time - only during backups with limited to no internet connection for security reasons.
Please make sure CCleaner is at the latest version due to a security flaw in their previous version.
Nice config!