I do not know how Caffè, and other Italian economics professors of the time, knew about Stefano and his whereabouts in that period, as Stefano had mostly grown up and studied in the US, eventually obtaining a PhD in economic history at Harvard.
BIS central bankers’ speeches  3  may act to shift down the neutral rate, the effects on the dynamic path of policy as it returns to the neutral are somewhat more complex. While the expected neutral funds rate is something that may be relevant, estimating and communicating a value with any confidence would be challenging.