Do you see an API for ListCategories and ListItemTypes ? I cannot remember where the namespace where they are implemented, but I believe it should give you what you want.

If bitlocker is disabled on both machines there should not be any problems with just swapping 2 working drives..

Get into bios and verify everything on the security page is disabled.
I do it all the time. Sometimes you end up having to reactivate windows, but that is simple.