If you’ve come here to ask complicated questions about the random production line changes that Jaguar made, then you have quite a few thousands of posts to go through.
That would be the dash from the later 1992 facelift model. It wasn’t an option, someone has retro fitted it.
Not by clever design. But search for “Marelli engine fire” for instances of shutting down cylinders through un-clever design.
There were different ABS systems fitted, quite a bit of work to change them. You can easily upgrade the pads, I use EBC yellow stuff. Front disc upgrades are probably not necessary. Lots of discussion about rear discs - vented or not, inboard or outboard. Recent thread Inboard brake question.
No idea on this one. There are many, many other places you want to be looking at for rust, never heard of any issues with the buttress area.