The Scania's have only 3 seats with BA sets built in.
That is the officers front left,rear right and left.
There is a BA set often referred to as the "drivers set" in the rear middle, but this is not set up for use as an extra seat whilst the vehicle is being driven and has different bracket holding the set in place.
The drivers seat for obvious reasons does not have a air set built in.
The rear of the cab could probably be set up for an extra seating position but this hasn't been an issue for us.
Backup BA is generally the second responding appliance which isn't usually too far behind the first.
As for the locker setup, most MFS appliances whether it be GP pump or pump rescue are fairly standardized throughout the fleet, which makes it a lot easier if you are tasked to grab equipment out of another stations appliance.
Regards, Mat