> There can be no such thing as multiple possibilities which are truly in the present, since we are doing whatever is possi- ble in the present. So any talk of multiple possibilities is referring to the future, not the present.

This doesn’t follow at all. Firstly, if we accept that the present has only one possibility then different possibilities can exist in the past as well as much as in the future (ie they can’t). Secondly, multiple possibilities can exist in the present, if we accept the many worlds hypothesis. It is not necessarily the case that there is only one present.