But, as my OP asks, is it actually being changed? Was Friday set in stone from the get-go, or was it the day of the week unimportant for a while, and then people were wondering, “Hey which day was Jesus killed on?” and they read through and figured, “Well, if he was killed the day before the Sabbath, then it must be Friday!”
In other words, is “Good Friday” a tradition based on the narrartive (in which case the days aren’t being changed, since they weren’t recorded in the first place) or something that was known from the beginning of the church?
I would suspect the former, feeling that Jesus’ early followers would have been more impressed with the idea that he died around Passover and wouldn’t have cared so much the name of the day of the week that it fell on that year.
In which case, the only things directly written into the New Testement are that Jesus was killed the day before a holy day/high Sabbath, that he arose sometime before Sunday sunrise, and that Sunday was the “third day” since Jesus’ death. Everything else then comes down to speculation and an attempts to make prophesies fit with what was written.
To me, the Wednesday hypothesis makes more sense, but the problem of the “open Friday” and the “third day Thursday” keep me from being satisified. (Torrey states that since Thursday actually began Wednesday at sunset, that it’s perfectly acceptable to think that Jesus died on Wednesday at sundown and have Sunday be the third day since he died… which is part of the problem, I guess, having to think of days defined differently.)