Mimi, you need to decide what gears you want before you buy the bike and then insist that the LBS swap parts until you get what you want. Using Shimano shifters on Campy freewheel, or vice versa, requires gadgets. But you could probably use any Campy freewheel with Veloce shifters. Or use Chorus shifters with a Veloce freewheel. But do any part swaps when you buy the bike because then you pay for the difference in price only and the LBS keeps a brand new part to sell.

Back in my day, bikes didn't come with "gruppos". You'd get a Suntour freewheel, a Regina chain, and Simplex shifters. Everything worked together.