If you want to use a Campy shifter , with a Shimano rear mech and hub, you have to re-space the coogs, so that the sidways movement of the mech matches the cog spacing.
There are conmpanies, like Marchisio, who make cogsets and spacers of various thickness.
usually you match the mech and changer from one company, to the hub of another. Anything else may need some experimentation, but you just need to get the spacing right.
You used to get some locknuts for Shimano freehubs, which has a cog, to convert 8 to 9 speed.
BTW, My Campy Mirage gruppo is definately an affordable, mass market product, pretty similar to 105.