Theoretically, they could; if the new vote was strongly in favor of LRT, something like 30 : 15.
But if it comes to another 24 : 20, this time slightly in favor of LRT, then the province cannot rely on that vote. They will know that the new "wish" of the council is as unstable as its old "wish".
They can't leave the corridor between Kennedy and STC without any rail service; but they can use their control of the purse string to sway the council in the direction they prefer.
Both [3] and [4] are out of question; either would be very odd politically.
Most likely, they would lean on the council and the Mayor to make sure the subway is still on the table.
Failing that, they might built a shorter version of the subway, using the provincial funding only (or, provincial plus federal if the latter remains available).