4x4 cossie brakes would fit and to be honest i think any 4x4 hubs will fit, they don't need to be cossie ones as the brakes will fit either way.

Although 4x4 cossie brakes are only single pot, however they are larger so would need 15's to clear them

You could possibly fit 2wd calipers as they are 4 pots, but i'm not sure if its a simple conversion. Can't see why not though. Again you'll need 15inch wheels