I think you need to add this line under [VRDB] section as well as under [AAVM] section:
ShowTaskbarIcon=1
Yes, do it.
Again, I don't have those lines and my icons are showing properly, so I don't know is it going to help you in any way...
A lot of 'default' values are not into avast4.ini file. It's normal and works.
If you add the value you won't harm the system. It will just confirm the default value.
