How to disable integrated Avast antivirus inside EMUI 5.0 (Android 7.0)?
I don't think it is possible , given the fact that it is integrated into the phone manager application, and is also a system application. 

I also have a Huawei tablet (EMUI 1.6)  which also has a tablet manager (package name com.huawei.systemmanager) but has a storage cleaning option which is said to be powered by Du Speed Booster. However I did several scans to try and find the app to no avail.

So I think it is not possible to separate the antivirus functionality from the phone manager app, so you either remove the whole phone manager package (if rooted that is) or stay with it. Otherwise I doubt if you cant explicitly find the avast as a package in your system.

You can still install another AV solution of your choice - (it really unnecessarily strains the phone resources) besides  I don't see the use of Antiviruses in android, if you obtain your applications from official trustworthy sources.



Huawei tablet manager (Storage cleaning functionality powered by Du Speed booster)