Are you swapping bell housings between transmissions of the same kind? Or, are you mating a bell housing to something else? You mentioned an adapter so I'm not sure I understood correctly.
If you are just moving a bell housing from one tranny to the other, it would just be, as you said:
bell housing (along with any associated gaskets if any)
Bolts
clutch fork
clutch fork clips, rubber boots
release bearing