I haven't read
THIS this through. You can do that!.
But you should be able to do the partitioning provided that the partition you want to muck about with is not the active partition (obviously!) and that there is no Pagefile.sys on the volume. That's easy to sort out from the basic setup screens.
IRQ's? Dunno. You should be able to if you go about the right way. Can you tell us what you are trying to do and maybe we can spot the step(s) you are missing.