One option is to retain the Shimano splined FH body and your Campy der and Ergo shifters then add a Shiftmate (I believe
#1 is the correct one) to best translate the Campy der movement to the Shimano cassette cog spacings. I use quite a few Shiftmates on different bikes for this very purpose. Far cheaper right off the bat then a Campy freehub body and cassette and the savings continue with each new cassette you need to get. Andy
Jtek Shiftmate Shimano Campagnolo and SRAM compatibility tables