hey moommoombaba,
when I began in the arcades, I chose layout B (ABC on the top) for those very reasons, coz I'm used to hitting top 3 buttons to perform roman cancels.
but after evaluating Litchi's gameplay and how to make it more comfortable on me, I decided to switch to layout A.
after enough practice, you get used to using the short, jab, and strong buttons for FD and rapid cancels so that's no longer a problem.
furthermore, having B+C in the jab/strong position actually makes it easier to tech throws in this game!
basically, evaluate your character and what button layout u think will suit you best. good luck!