Man, I just wholly disagree with you on this at this time, or maybe I'm arguing a different point and criss-crossing with you.
Quoting myself because I like to smell my own farts:
In the scope of a universe being billions of years old, is it that far-fetched that a civilization 1,000, 2,000, or even 10,000 years more advanced than us exists? That would explain both the technological capabilities and the time it would take them to get here. Even a difference of 10,000 years out of 14,000,000,000 is a variance of less than 0.0001%.
Make that 100,000 years and you're still at less than 0.001% variance. 1,000,000 and you're at 0.01% variance, and so on. No need to explain the near speed-of-light travel at that point.
I'm open to other theories, like they've always been here/there's something interdimensional going on (which I guess could fall under "natural phenomenon"?), but I'm shocked you think that the eyewitness accounts and the tictac video are somehow human or technological errors.