So, I have searched if anyone mentioned Wreaken in combination with Raxxla and it seems that most people have ignored the Codex entry for the Wreaken corporation.
In the codex it says that Wreaken is one of the oldest corporation, being "over 1000 years" old. That puts it right into the ballpark of the first mention of Raxxla which, surprise was also just over 1000 years ago.
Also Wreaken is described as being very thorough in their survey of systems, and Wreaken was at the front of exploration in the early times. This makes Wreaken the prime candidate for having found either Raxxla or the Omphalos Rift. This would make Zearla and Ega (home system of Wreaken Construction minor faction) prime candidate systems for starting an investigation. Zearla is an ironic one: Zearla is probably the first system players encounter outside the starting area and the Wreaken tourist beacons would be the very first introduction to Elite lore. This would be a "voyage everyone has to take for themselves".
As for Omphalos Rift: I suspect that the Omphalos Rift might be a traversable wormhole, or even further, it could be a system of wormholes connecting remote places in the galaxy. Looking where we have permit-locked regions, it would make sense to have some kind of shortcuts to those remote places when the permit locks are finally lifted.
Another interesting thought about Omphalos Rift: Since Omphalos means navel, Omphalos Rift might also reference the act of "cutting the umbilical cord", which would be fitting with the toasts "to the mother of galaxies".
So, back to the Ega-system, which is unremarkable, right? Except we have there the "Omega Infantry Headquarters", which could have the function of protecting a secret. Then there's an Observatory on the (south?) pole of a moon; perhaps the antennas are pointing towards something? Being on the pole, the antennas should always point to roughly the same region in space. Has there been investigations regarding other observatories?