Upgrading old Campag groupset with modern parts

Well naturally I'd need new hubs, I'm going to build a new wheelset if option 3 seem like the best choice.

Henry, the bigger reason why I want to go for the campag is that I found their hoods to be super comfortable, the shimano one felt weird and I've yet to tried, and the Centaur groupset is something not only I've tried before but also have an all-silver groupset that's much fitting to an old bike.

I'll see what I can do with changing the downtube shifter to an indexed one, if it's enough, then perfect, if not, Centaur's definitely an option once I find out the rear spacing of the bike is (may need widening to accomplished modern hubs).

all of this is great information, thank for making it easier to figure out the next move.

I still think a full centaur gruppo plus some campag hubs laced to open pros (or something like that), is the way I'd go about things.

But you could try and pick up some cheap ergo levers from EBay or something. I've never done it, but converting these to 8 speed indexed should not be a big problem. This would give you indexed gearing and move your shifting to the bars without much outlay.