1. yes. As I know - may could happen I'm wrong - /Library/Extensions/ contains FTDI drivers, one of them is starting with FTDI.....kextt, the other one simply calles usbserial.kext
2. yes. I could find te Apple FTDI kext file in the appropriate library. (I do not remember exactly for this library, but somehwere in /System/Library/...whatever contains, the point is, I found it).
3. I have no idea, this is an original FTDI chip on it or not. I'm going to check it. What is sure, with the 3rd party driver was working properly (FTDI AN-134 driver was, if I remember correctly).
How do you mean "to contact FTDI directly" ?
My main problem is, I do not understand, how FTDI driver is works. Also I do not understand, standard FTDI why doesn't work with ANY chip??? Who cares about chipset, whenver FTDI is FTDI.
In case of Apple FTDI driver doesn't handle my pretty shitty chines clone FTDI card, what a hell I can do? Is there any workaround solution? Do I have to install a Window$ on my MacMini ot handle Arduino???
I'm really upset, because of this problem! Something was working properly and now doesn't, without any warning. I'm satisfied with my computer, but I'm not satisfied with this solution...

Please, somebody help me!