Yes, animals are intelligent enough to manipulate a behavior in order to receive special treatment. This is precisely what training is. Animals learn that behaviors have consequences, some good and some bad. They then control their behavior accordingly in order to encounter more positive consequences. In the case of the falsely pregnant panda, she may have learned that when she is pregnant, she was well taken care of. Thus, she mimicked those symptoms in order to continue experiencing such an elevated level of care.
Yes I do believe that Panda bears are extremely intelligent animals and absolutely capable of faking a pregnancy to be rewarded with special treatment. Similar to how humans behave, animals can act in a very manner to be rewarded for certain actions. A panda who has been pregnant before would remember her feeling from prior pregnancy's.
Yes, animals are intelligent enough to fake a behavior to get special attention. Animals like to be treated well just as people do. An animal will fake a behavior if the animal notices that it is being treated better by doing so. Animals are intelligent enough to figure out when they are being treated well.
Without sufficient communication, animals are unable to fake this kind os behaviour to get special treatment. The reasons people do it is because they can verbally acknowledge what treatment they'll get. Animals are unable to communicate in this sort of way so it is highly unlikey that this behaviour was faked because they thought that the end result would happen.