You Can't Disprove a Miracle

[Angrboda]

Even if those stories weren't lies or exaggerations, they are still, at best, eyewitness testimony.

(And we have no reason to think it was even written by eyewitnesses.)

Eyewitness accounts are not sufficient to establish supernatural causation. The reason for this should be obvious.

Using the same example above, are eyewitness accounts of the event, timing, and context sufficient to increase the probability of an event having a supernatural cause versus a natural one?

You're still arguing that low probability events equal miracles. No they don't. Low probability events equal low probability events. The probability cannot demonstrate that it has a supernatural cause, only evidence of an actual supernatural cause can do that. Eyewitness accounts to unexplained events, even if held to be reliable, even given certain context, do not show the supernatural.