In order for the hypothesis that the pyramids were in fact constructed by either a predating ancient civilization such as Atlantis, or through alien civilization, to be true we would have to see some direct evidence that would support this in Egyptian archaeological records.  This evidence could range from anything from foreign materials native to another geographic area, other advanced materials or not previously used in Egyptian construction, or perhaps building methods that greatly differ from ones previously used in Egyptian societies. However, when examining the construction of the pyramids, there is evidence that suggests the opposite. There are clear markings on some of the stones slabs used in construction that are derivative of tools that were commonly used in construction during that time. Additionally, there are written logs and accounts that go into some detail the construction of pyramids.  And virtually no evidence that would suggest that there was some intervention in the construction of the pyramids from a society outside of Egypts.  Additionally, there is evidence showing the methodology used to construct the pyramids slowly changing through history, if there was reason to believe that these methods were  from either another ancient society, or from aliens, then it is likely these methods would have already been perfected, or the Egyptians would be too unfamiliar with the techniques to modify them. 

Similarly, in order for the theory that Mayans and Egyptians were a product of hyper-diffusion from Atlantis, to be true there would need to be something in archaeological records that supports this, or offers reason that would suggest this is even possible. The main example that hyper-diffusionist point to when arguing their case is of course the pyramids. While the pyramids from the two perspective cultures do share the obvious similarity that are in fact, pyramids, the similarities do not extend far beyond that, though both held very important religious and cultural significance in the two societies this importance manifested through their cultures in drastically different ways.  Other evidence that would be useful in giving this Atlantean hyper-diffusion theory would be things like similar cultural customs, religious practices, or societal hierarchies would suggest that there is some link between the two. However, the Mayan and Egyptian societies were in fact very different.  Additionally, there would be likely be some type of recorded history in either of the cultures that refers to this common ancestor.  

As with any hypothesis in order for these to be proven true they needed to be tested and there must be evidence that conclusively supports the theory. Neither of these examples come close, to providing anything outside of circumstantial evidence that would suggest that they are too. Further confounding these hypotheses is that there is no physical evidence that Atlantis ever existed.  In order to support either of these hypotheses  you would have to ignore very direct evidence that supports the opposite arguments, and deny the recorded history from both of these civilizations.