I did it, but haven’t received satisfactory answer yet. Thank you for your help.

I am testing “CruelSister” CF settings (with Auto-Containment).
Hips are in safe mode, and Webfiltering + Viruscope + Windows Firewall all are off.

In terms of “low impact system”, this combo (Avast Free + CFF) is perfect.
And “CruelSister” settings claim to be capable of stopping everything dangerous (I am still testing this). Everything unusual, with this settings, CFF runs in Auto-Containment (avoiding damages). Lots of experienced CFF users say that CFF with this settings doesn’t need antivirus. I am testings all this.

However, for many other reasons, I still believe we need an antivirus.
And I am afraid that “CruelSister” settings with Auto-Containment are redundant with Avast Free (and it could interfere with Avast).

Thank you for your answer