The School structure is the big question mark here. Presumably a lot of the work goes on in the actual disciplines, which raises the question of whether you'll actually have that much to do in some of these roles, and whether you'll be in the position of trying to harmonise practices when it doesn't always make sense to do so. That can be a bit challenge, as the disciplines can end up pushing back. Some of the roles (e.g. Research Ethics, pastoral) lend themselves better to a School role than others (e.g. UG and PG programmes, also Research can be problematic when several REF UoAs are involved). A lot depends on the School culture and how cognate the disciplines are.
A couple of comments on the roles:
The Discipline Officer role will involve a lot of fire-fighting. Does it come with line management responsibility, though? That can be good on the CV.
I avoid pastoral support roles on principle as it annoys me that it's always women who pick this stuff up.
Admissions / recruitment - pressure when the course is under-recruiting (though, again, would you be overseeing this across the School but with individual admissions tutors in charge of specific courses, in which case you wouldn't be the one under the cosh?)
Re: The restructuring is apparently going to improve interdisciplinary research and teaching
Restructurings never do what academics are promised they will do. They are exercises purely for the convenience of University senior management. I'd be very wary of thinking that this is going to yield a wonderful new interdisciplinary culture.
Also beware of how the professional services team will transition to the new structure. It will likely take a few years to iron out their new processes (which won't be helped with difficulties recruiting to administrative roles at the moment). If you're going to be relying on them in any way (e.g. as Discipline officer, UG director), you may well find yourself taking on basic admin tasks while they sort themselves out.
Perhaps I'm jaded though! Having done big admin roles for nearly 20 years because I've had no choice, I wouldn't be sticking my hand up for one!