Good points GM. My assumption is the 2B has a lot farther to go than the 1B in most cases and in some cases may still be moving when receiving the the throw. Though the distances are shorter on SB diamond than BB diamond.IMO, it depends when the 2B gets to the base. If they are there in advance of the throw, they should use the same footwork as a 1B (i.e., be prepared to stretch w/ either foot). If they are on the run, then it will normally be the left foot. If its not going to be a close play, they should can catch the ball and THEN still have plenty of time to find the bag - no need to anchor unnecessarily.
In that scenario, left foot - yup.
Personally, I don't like 1B crashing bunts. If it's on the 1B side, the P or C should be fielding the ball, depending on how far it rolls. If 1B is making the play, their momentum is moving completely in the opposite direction of where they need to throw which makes it a much more difficult play. The only time I'm okay with 1B making the play is if the bunt is far enough up the line for them to field the ball and tag the runner unassisted.
If your personnel dictates leaving 1B at home, then you need to bring the 2B way in or else there's just too much ground for the P and C to cover and a good bunter will eat you up. I have visions similar to a soccer PK where the shot is right at the keeper in the center of the net, until they dive out of the way.
Let me qualify my previous statement by adding that I'm dealing with 10U girls. My tune may change as the abilities of the players and speed of the game increases as they get older.