A little self correction regarding the item get messages, while it's true that the original Japanese game places the item name on its own row for treasure chests to avoid double spacing due to the space intended for the magic icon, it turns out that the game treats the messages for hidden items in the same manner as yours.
Still, while the issue with the "x"-icon is solved in your patch, I noticed that the original game isn't consistent on how it chooses to display it between the battle and regular menu:
Perhaps an oversight due to the developers originally intended to allow item names to be 9 characters long intead of 8? ...there's at least screen space to allow for it. But it may be a bitch to implement.
EDIT: Hmm, the different way the game treats the "x"-icon is seen in both item and magic menus...