First, does Ukyo actually have a schoolbag? The only time I saw her with one at all was when she dressed in the female school uniform in that one anime episode.
Vaguely recall seeing her have one a rare few times, however i dont think i´ve seen her actually carrying it with her any time...
No guarantees though, i can´t recall any time when it´s showed without any doubt to be specifically hers.
Second, how does Ukyo get, and afford all those okanomiyaki things in her intro chapter? Especially that grill ring? She must have planned that or used it before long before she caught up with Ranma, right?
Author fiat or she is already working before she arrives "on stage", and considering the ease at which she sets up shop and gets customers despite the "issues" she probably DID earn some very decent cash from her cooking well in advance of getting into the story.