Thought about your comment some more, and I am not sure any lawyers will be disbarred when the stock disappears, because I am not sure that any of them ever guaranteed perpetual life for the stock and I am not sure any lawyers were in a position to make such a guarantee.
If you recall, it was the bondholders that said that it was their intent not to affect the survival of the shares, which is exactly what you would have expected them to say at the time. This was, after all, in the immediate aftermath of the original bankruptcy filings and one of the prospects at the time would have had to have been converting debt to equity. Thus the bondholders would certainly not want to cut short the life of the stock.
As for "Arpad agreeing that the stock would survive," what could he know? He had demonstrated on the Yahoo board incredible ignorance of insurance accounting and the regulatory process before, during, and immediately after the bankruptcy filing, then, when another cohort was unable to find a lawyer to take the case, he made a silly attempt in the courts to force an equity committee into the process. He was not a representative of the company and from all appearances no representative of the company made any statements that possibly could be interpreted as guaranteeing the survival of the shares.