Welcome.
When the 645D first came out, a lot of people were testing various 645 and 6x7/67 lenses with it and talking about it in the
Medium Format Thread. I don't recall the results with specific lenses. But I do recall that the
SMC Pentax 67 55mm f4 generation lens, the
M* 300mm ED (IF) and M* 400mm ED (IF) were rated high. Others not as good when mounted on the 645D.
I suggest you post that question in the Medium Format Thread and the people there that have the 645D can help you.
Optically, the newer 67 generation of the 45, 90 and 135 are no different than the previous 6x7 generation of them. The 67 200mm and 67 55mm did undergo an optical change from the previous 6x7 generation, however.