I like to think of abductive reasoning as the basis for science that explains natural processes that happened in the past -- like astronomy and geology and evolution -- where experiments are too big to conduct or processes too slow to observe in real-time. So we propose mechanistic explanations for nonobvious outcomes like the formations of stars, or motion of large land mass via plate tectonics or glaciation, or long-range organism speciation over millennia. That's the role for abduction, to explain how all that happened.

Here’s a good page to read on that:

https://plato.stanford.edu/entries/abduction/#AbdVerBayConTh...

No, but agreement with priors is one way one might choose between possibilities.

For example suppose you go outside and the streets are wet. Perhaps it rained, or perhaps someone drove a fire truck around spraying water all over the streets. You might select the former because of its higher prior probability.