I just tried and the results are:
1.) Don't know what you meant by parametric objects, but I tried the DOF with a cube and disc and everything works fine
2.) This seems like a feature request, so I will add it into the corresponding section here on forums
3.) This works for me regardless of the "movie camera" setting in the c4d camera, so it was probably fixed already
I will move this thread to resolved. If you find another bug, feel free to report it ;-)