Regarding filters...I've been reasonably successful in getting original Hasselblad filters from Craigslist. It seems a bunch of folks around here who used to use 'blads packed bits away when they went digital.
Be aware that if you choose to use threaded filters and a bayonet adapter, you will not be able to use the Hasselblad bellows lens shade. It was acquiring one of these lens shades (and B50 and B60 adapters) that started me on my quest for original filters.
I don't plan on bellow shades but that is very important information to know!