Actually, it can. Using mathematics. Given that all humans in Europe are estimated to have shared a set of common ancestors roughly 3000-4000 years ago, we can use 150-200 generations as a starting estimate. For these animals, they go through 1 generation per year, and a few hundred thousand years is plenty of time for a set of descendants to spread across an ocean basin.
Definite, no; as likely as most hypotheses are, yes. I have complete blurs in form in at least 3 taxa offhand between 3.8 to 3.2 and 2.4 to 2.2, 2.4 to 2.2 and 2.0 to 1.8, and 2.0 to 1.8 and 0 MYA. How that is not a complete line with short intervals is beyond me.
I have tested hypotheses to that effect. How are they not scientific?
This is true to a certain extent, but it is an unsupported claim, and does not help with the statistical probability of their being ancestors.
How about holes from a source that has a better track record on doing purely scientific arguments and on honesty?