I forgot to mention this before.. Gradual Petrification seems to behave buggy in both FF2US versions.
Anyways, the more important point that I've just found out...
The freezing in FF2US is caused by the following...
Timers are used for Paralyze and Sleep... (both status can't be inflicted at the same time for obvious reasons). This timer unfortunately is shared with the Stop timer. When Paralyze or Sleep status is followed by Stop status, the game is unable to "release" the target from the Paralysis or Sleep. When done on your own characters, the character never gets out of the status (you can still heal the character so they are not stuck forever, it only lasts for the battle anyways). When done on the enemy, it causes the game to go haywire and freeze.. depending on the situation. I got the Kary (FF2US name) to do "useless" hits where the it seems that an attack is made on a target, but no damage is dealt (this only occurs when there is a friend around, because the Kary executes an entirely different script while alone).
Ironically Poison is not affected since its timer is described in BSiron's FAQ (but has its resistance bug), so go figure.