The meeting idea is not usual, yes.
As the clerk says, since we don't have a precise date, we should send an initial notice of this motion, as a courtesy, to the independent members, who will know exactly what to expect. On the day of the last testimony by the last minister, those MPs will get a reminder.
That means that all our colleagues in Parliament will be able to propose amendments, even if they do not all follow the committee's work. I am thinking of the Green Party, for example. Those MPs have to have the same deadlines as us. That's how it has always been.