Considering what you've written there, wouldn't the obvious be to have Christ die and be resurected at the winter solstice? The winter solstice is undoubtedly the time of the Death and Resurrection Show, so why Easter when that is simply a time of birth?

Christianity is an Iron Age religion. Not a Stone Age one, so presumably it was replacing Iron Age dates with its own.I know Xtianity has last a couple of thousand years, but can we truly say that the previous religions were constant for the three thousand years between the building of Newgrange etc and the start of Xtianity? Perhaps we can, I dunno.

What I do know is that in Ireland the biggest time of celebration and gathering was Lughnassa (the month of August is called Lughnassa in Irish) and this was still happening into the nineteen 60s. Tales of Patrick dominate Easter and Lughnassa, but rarely do they speak of winter celebrations. In fact I don't think there's any mention of it. The most important festivals in Ireland seem to have been at Easter, Beltaine and Lughnassa in the 5th century, with Lughnassa lasting by far the longest into the Xtian era.

All good thinking material.