I'm pretty sure you could get the Zell card from Zell's mother. I can't remember where I collected the others though!

As for the 'increase' comment, I'm not really sure the rate, but I've encountered several times where 'increase' and 'increase to 100% chance' were the same. I think it's just poor wording, but not necessarily wrong.. I mean it DOES 'increase', doesn't it?