It does seem like the right time to do it, considering her songs are now mixed, and it would be unexpected.
I think she could perform the new single or she'll at least perform a new song. I don't think she'd dare not to tbh. Plus it'd be some promo for the new single in Japan which will be useful.
I'm not getting my hopes up. I hope she does some new songs, but if she doesn't I won't be too surprised if they want to keep them locked up until their official release.