I must have been saved a lot of misery, judging by the postings here, by my schedule ... I typically get up and boot around mid-afternoon (EDT), and got the avast warning in its tool-tray icon. Opening the interface, I got that background-services notification which included a link to start the "missing" services, which I clicked.
The only iffy part was when Win then asked for permission to run two exes, one of which had "proxy" in its name (probably related to the emergency update). After a moment's hesitation, I OKd both, rebooted, and afterwards avast and (as far as I can tell) the whole system were just fine again.
So I got probably the quickest and easiest repair right from within the interface itself. Probably a case of lucky timing relative to Avast's release of the UI fix. Certainly I was never faced with anything triggering a panic reaction, simply because I missed out on the hours of waiting and trial-and-error that others went through.