Of course you can get all fields, but not in a single API-request. The reason for that, certain field combinations are not allowed.
This is all documented. To see an example of such documentation, here is an example.
Look at the description of "ConversionTrackerId".
At the end you see a "plus" image and the description "Not compatible with the following fields:"
Click on the plus to actually see the fields which you cannot use with ConversionTrackerId.