People are speculating they shot some of the Sledgehammer scenes before the script was rewritten when Harrison broke his leg so they would have Leia in that.
It’s certainly possible. Honestly it’s unclear how far a lot of things got before they were changed. Which is why I said earlier it’s sort of a benefit to them that they kept that whole process mysterious when talking about TFA’s production. It’s entirely possible that they have a completely unspoken of subplot that they could slide in. Or not.