Can sound waves be made to project 3-D shapes, like a reverse sonar? Can sound waves be manipulated to project 3-dimensional shapes or forms, like a reverse sonar?
 A: The question could be rephrased as, is it possible to create an analogue of an "image" of a three dimensional object acoustically? 
The answer to this question is clearly yes, provided that the wavelength of the sound used to do the imaging is sufficiently small compared to the object being imaged. One example is in the energy industry - geophysicists use seismic and acoustic waves to construct three-dimensional images of oil and gas bearing structures underground. Another example is acoustic holography. This is a technique for reconstructing an acoustic "image" of a vibrating object, like a car engine, by sensing the magnitude and phase changes of its three dimensional sound field using an array of microphones.
As far as generating a synthetic acoustic "image" of something represented as a sound field, there is the  (relatively recent) technique of wave field synthesis (see for example the Wikipedia article on this). As @dmckee alluded to , this uses a phased array of speakers to artificially generate sound "sources" that replicate the perceived sound field in an environment. Conceptually, one could achieve this effect with synthetic aperture (i.e. moving sound sources), depending on the frequency, but there would be quite a few complexities to implementing it.
(Note added in edit  - the question originally asked about dolphins using such techniques to communicate. This has been edited, and I will remove this section if it is not relevant after the question's edits stabilize)
The second question , do dolphins communicate this way, the answer is less clear. From what I read of the article, I am surmising that the researchers are using time-frequency signal processing to try and detect and classify patterns in dolphin "speech" that might be  repeatable and something like phonemes in human languages, and then determine whether these sequences are forming larger sequences like words and sentences. I am not sure they are thinking in terms of the dolphins creating acoustic holograms for each other. It's an interesting question, however. I am no biologist, but it seems less likely than the hypothesis that dolphin communication is probably more like time frequency sequences, because communicating with acoustic images would seem to require some form of synthetic aperture (swimming while communicating).
