I don't understand. According to the links you posted, you were asked to send a link or .zip and/or additional info to Avast Team directly. If you don't, how do you expect them to know how to do this?
Besides that, all that the customer needs to do is to click once in the Sandbox option to allow your program to work (not inside sandbox), and another click in "remember", so Avast's Sandbox won't ask again. That seems to me much easier than instructing to change AV.
About blocking connections, it depends on the firewall, which could be from Avast or not. As with any other tool, it needs at least one time the approval of the user, and then the firewall knows what to do.
I don't have any real answers here, specially because I am a simple user, not an Avast Team member, but for some unknown reason, some miscommunication is ongoing here.