Specifying own mobile number as "Friend"

Can I set the phone number of the mobile that Avast is installed on as one of the “Friends” to accept commands from?

It’s not a silly as it sounds, as I can send SMS’s that appear to come from my phone by logging-in to my O2 account.

yes of course you can do that. however, notifications then will go to your own phone.
however, you can uncheck “only allow commands from friend numbers” as there is still the PIN to protect your phone. then commands from all numbers will be accepted.