Even if he always used TOR/anonymous IPs, when accessing his @gmx.com account, with the number of sign-in's he had, it must be an absolute certainty, that he want through rogue exit nodes or some other de-anonymization methods we are not aware of, but deployed by gov. agencies.
I think that "IP leak" is extremely dubious and is predicated on both misunderstandings of how freenode worked and an incorrect assumption that no one else was running Bitcoin early on.
It would be great if you could elaborate on that technically. Are you saying Satoshi wasn’t running a node that day? or there were more than the two nodes? I plan to read the code tomorrow they were running and look at the debug.log and would like to understand what you are trying to say technically.
The world is a big place. It's likely that in 2008 thousands of people had the right skillset to create Bitcoin, any one of which might have done it.
As long as Satoshi wants to stay hidden, we're not going to find them.