Wow didn't know they no longer existed 4x5...
Yes I get the fact you are planning a hybrid workflow.
So shoot color and convert to BW post-process, I don't think you will have bad results.
If I felt I wanted the relatively grain-free color aesthetic of color converted to BW, I would be very careful not to reveal two shots side by side derived from the same image where one is color and the one next to it is BW. If I converted an image to BW for my portfolio, I would lock it down virtually as BW and wouldn't allow color variants to hit the internet.