i'm not sure spending the next two years refusing to have a (public) view on Brexit is doable for Corbyn. At the moment he can brush it off by focussing on the Tories and their deal, or on avoiding no deal, which after all is the priority. But going through a general election and then an entire renegotiation process with the EU while refusing to ever say if he thinks his deal is better or worse than remaining? That's a tough ask.
Its also unclear what would happen to the Government duing that period. Would ministers also be expected to stay neutral during that process if the Prime Minister was? I dont see how he can maintain party discipline now when most of the senior (shadow) ministers have already said they'd back Remain, that cats out of the bag. But if he doesnt at least try to maintain discipline and pretty much every senior minister goes around saying that Remain is the best option for the next couple of years, well, that'll destroy any semblence of leadership.