23 wIll never be used again. The stands opposite the old Deltas, (stands 170 and 171) will have passenger access, either by a road crossing the taxiway (as 23 won't be a runway), or I've heard it mentioned that a tunnel is going to be built across to them.
Most of the big (code JW or JX) stands on T5 will be what we call 'MARS' stands. I can't remember what that stands for, Multi-choice something something. basically they can fit two small or one big a/c on the stand, Like 127L and 127R for up to 757, and 127 can fit a 747.