See, for a story like yours, I think modern religious practices and beliefs are irrelevant. That said, current archaeological practice seems to have swung towards thinking most bog bodies were not human sacrifices...but there's still other evidence for human sacrifice among Celtic peoples, and your story didn't trip my ARGH NO RESEARCH meter, personally. And there IS that issue with a lot of historical settings, especially when you go back further--that you run into the wall of We Just Don't Know and have to extrapolate (this is largely true of pre-Christian Celtic religious practices, for example).