1 - No passports.
2 - T4S, almost certainly a bus gate.
3 - Yes, off the BA456, up a couple ramps to the top floor, walk along to the central area, security off to your left while passports are straight ahead. Relatively quick, then you just head downstairs and go through duty free (where the lounge is).
4 - There's a Royal Air Maroc in the evening on which Iberia codeshare, so if you do miss your connection you should be put on that. You have an hour, if the BA456 is on time it is more than doable, bags may not make it though.