This one has me a little confused. The pitcher, while in the set position, starts his preliminary movement to bring his hands together in front of his body for the required 1 second pause. Typically, most pitchers make that "circle" with both hands where the ball and glove meet at their face/chin but not always. Anyway, while in this motion can the pitcher immediately turn and throw to first base before the hands and glove come together?

At any time during his preliminary motions, the pitcher may step and throw to a base.

Right, the pitcher need only "pause" in the set before a pitch. There is no restriction to pause before throwing to a base (OBR 8.01b).

P-Sz