how does exactly Grand Cross work? what chance has each status of hitting the characters?

Well, I always assumed the negative status effects were random, but I have no idea as to the exact algorithm used which determines the probability of an effect occurring.

FF Wiki doesn't say much on the subject either, other than it can afflict Instant Death status on a character and Zombie as well at the same time, preventing them from being revived (you first have to use a Magic Tag on them to remove Zombification before reviving them).

Other than that, I have no idea.

thanks. I don't know why I got no mail notification of this!

I have never looked into the mathematics involved. All I knew was that equipping status protecting skills and auto life made him easier than Kuja.

the status effects are random. not only can it instantly kill a character, it can reduce someone's HP to 1 as well.

yes, it can inflict ALL status effects. I wondered the percentage of success!