Yes you can. But you don't need to as Shimano 11 and camp 11 work with either. You just need camp cassette with same brand free hub or Shimano cassette with Shimano free hub. But either will work with either brand drivetrain.
You can select Shimano at point of sale with Wiggle so answer yes you can fit Shimano freehub. But it does not matter as campy tolerances and Shimano 11 tolerances are so close that you can use either brand cassette and chain with either brand drive train. For eg KMC 11 speed chain is cross platform. This info is verified by numerous tests available to read on line. So if you have with campy freehub, fit camp cassette and will work with Shimano. Or vice versa.
Yes. Info on wiggle page for product. Shimano free hub does 9/10/11. But if you buy with lighter campag free hub body and put a better campag cassette on, this will still work fine with Shimano system.