Lewis,
Frankly I have no idea what you are going on about.
You refer to bidirectional cones, are you to referring to light cones in Minkowski space? If so what is the relevance?
Where does Hawkins (or more precisely Hawking) fit into the picture and what about these peer reviews you refer to.
The mathematics behind space time expansion and why the Universe is not expanding into existing space is actually straightforward.
It does require a command of General Relativity and an understanding of the
RW metric on which modern cosmology is based on.
Regards
Steven