Yes, it fits all types of bikes. Even very small bikes can be attached. Only with the thick frames (with integrated battery pack) it will probably not work. Best regards Thomas

Yes, sure, get some carbon frame protection from thule and you won't have any problems....I ride carbon gravel bikes as well as downhillers with the carrier...I have them with the front wheel to the rear so that they don't flutter during the ride....

The maximum wheelbase is approx. 125 cm. Your problem will also be the max. 20 kg restriction. A cargo bike is usually heavier.

Yes, there are two different keys. The number code is then written on the respective lock and key and is visible from the outside. However, you can buy locks with the same number code from Thule so that one key fits all. I have it on my Wingbar Edge profile. On the Thule homepage you can find out all the information very easily via the configurator.