Excellent comments; please keep them coming.
I anticipate working exclusively with the 80mm Planar for the first 6 months to a year before even considering another piece of glass. I feel like I need to learn creative discipline and proficiency with the 500CM and 80 Planar before expanding my options. At least for the time being, it seems like options #1 might be my best choice. If I'm not changing focal lengths with different lenses, I likely won't need the versatility a bellows-style shade would provide. Option #1 is especially interesting to me considering that bdial states I can use a stock lens shade with a B60 filter attached. I imagine simple will mean less distractions as I learn Hasselblad and relearn film.
That is correct the shade fits over the filter(s) of course you loose some shade effect as the glass pushes out but one filter is never going to be a problem. I'm sure you will enjoy they are wonderful tools.
You will need to push to 40mm glass before the B60 is too small and up to 350mm at the other end. the 60 is "universal". Shades the same only difference is the length. So a 50mm lens shade 40668 will it on a 150mm lens, it just won't be very effective.
in my opinion, filters are one of the feww weak points of the hasselblad system. they are all terribly expensive and the Hassy filter bayonet do not always stay put very securely. Iended up with a set of Tiffen filters in Hassy mount. the price was reasonable, and they are just as good as the pricy name-brand filters. the Hassy shades have a bajonet also and work perfectly with or without the filters.
I struggled with this conundrum when I first acquired a Hasselblad. I ruled out a proshade as being too big and unwieldy. I bought a Bay 50 (I have the older C lenses) to 55mm adaptor and used Cokin filters but I wasn't happy with that. In the end I bought Bay 50 Hasselblad filters and hoods for my 80mm and 150mm lenses. The hoods fit onto the filter and it's a much neater solution. If I want to use a filter other than what I've got in Hasselblad fit I can use the adapter and Cokin filter instead. I also use Cokin filters on my C Distagon 50mm, but that's another story...
Hasselblad filters are very expensive, but if you're patient you can find reasonably priced ones on Ebay sometimes. The Milo and Aroma filters tend to be cheaper than Hasselblad filters - I don't know if there's much difference in quality. I bought a Chinese Widepan hood for my 80mm. It's plastic but quite sturdy and fits perfectly.
I use options 1 and 3:
B60 for my most used filters (Y2 and Polarizer).
Proshade and 4x4 Lee filters for more specialized uses (ND, R25...).
With the Proshade, you can also use B60 and 4x4 at the same time.