AD9082 : specification clarification

Dear all,

Reading the datasheet I am unsure of my understanding : what is the maximum sampling rate of a single ADC ?

It is unclear (to me) whether it is 3 or 6 Gsps ?

The same question would hold for the AD9081 : 1.5 or 4Gsps ?

Also, can it support baseband I/Q operation at the ADC input and DAC output ? In such a mode, is it possible to use the DUC/DDC ?

What does observation Rx mean ? I suppose it is intended for channel feedback loop (DPD, equalization, etc...) but how does it translates ? How does it affect my design if I want to use the ADCs as  independent input channels ?