By their very nature soft openings are unpredictable, but here's some speculation.
Fallon's gift shop opened up on January 21st, the ride first soft opened late in the day on March 2nd, the grand opening was April 6th. The actual soft opening hours were short (1-2 hours) in the beginning but gradually expanded to park open-close toward the grand opening.
The Fast and Furious gift shop opened up a week before Christmas.
Chances are VERY high for soft openings sometime in February if you use Fallon dates as a guide, so that week in March is fairly likely based on that.