1. Don't have any specific data, but your tire supplier should be able to give you written documentation as to the durometer ratings of each tire type.
2. White non marking tire have ~15% lower durometer rating (hardness) than black tires due to the lack of carbon black found in black tires as you say.. Therefore they will wear out faster -~ 15% faster.
3. Being softer they are subject to more cuts which leads to increased chunking.
4. The benefit is in cleanliness of the floor (tire marks elimination) plus being softer they will have more traction, important if water is present. - on ramps outside yards, etc.

Hope this helps and also excuse the spelling of tire instead of tyre - give my apologize to the Queen. See we American butchered the Queens English once we cancelled the contracts with our former landlord. We speak Americanese. Just a friendly jest. Plus, we drive on the other side of the road.