Re: Buying 156 JTS... all sorts of questions first...!
I swapped my 1.8TS for a 2.0 JTS and it was a great car (until it fell off Snake Pass backwards at 60......)
Loads more bottom end torque than the 1.8 and I liked the upgraded interior.
Mine's now been gone for 9 months, but I'll try and remember some things to help....
In answer to your questions:
1) No the outer aircon dials don't click. (I don't remember the middle one clicking either, but I can't be sure...)
2) The pocket is an integral part of the door panel moulding (I think). I had mine off but didn't spot any obvious separate part....
3) My buttons started to wear too, but I can't advise on replacement I'm afraid.
4) & 5) Can't help I'm afraid.
But 6) NO! The info panel should come on straight away when you turn on the ignition. That is an issue.
In general though I liked the JTS. Its basically a TS engine but with a different fuel system, so it sufferes the same foibles as the TS did.
My problem with my JTS was that the engine mgmt light used to come on regularly about three or four times a year.
The garage checked it out twice (once under warranty, once cost me an hours labour...) They reckoned the sensors on the JTS are far too sensitive. It was a cat sensor that went out of tolerence for a moment each time and that locked the warning light on.
In the end I spent £37 on eBay for a engine mgmt cable & software to allow me to reset the light myself.
Other than that, the car was great. Ended up swapping it for an Audi A3 S-Line 2.0TDi with the DSG gearbox (I always fancied a Selespeed but never got one...) and that's a very different car, but I look back fondly on both my Alfa 156s....
I'd worry about the faults on that one though - suggest you try and find another example. The car's OK in general but that one sounds iffy...
2004 Silver Audi A3 2.0 TDi S-Line DSG (eBay!)
OEM Xenons (retro-fitted), PIAA silicone wipers, integrated Parrott CK3000 bluetooth phone kit, O2 XDA2 PDA/phone with TomTom wired GPS
Ex - 1999 156 1.8TS SP1 (1999-2003) + 2002 156 2.0JTS Turismo (2004-2006) (fell off Snake Pass backwards at 60mph...)