Luke 22:1Now the feast of unleavened bread drew nigh, which is called the Passover. KJV
This is why many incorporate the 7 days of the unleavened bread with the first day of the Passover as you stated that there are 8 days of unleavened bread for why Luke refer to the first day of Passover as also the first day of unleavened bread.
One can surmised that is why they called the 7 days of unleavened bread also as Passover even though only on the Passover day is the lamb to be sacrifice, cooked, and eaten on that day with the unleavened bread whereas the 7 days of the unleavened bread, the lamb offering is not to be eaten but just the unleavened bread.
One can assume clarification was needed for understanding Acts 12:4 as not meaning the actual Passover day itself for why Easter is used once again in the KJV when the 1599 Genevan Bible had it as Passover, but we will never know for sure other than it is not wrong to use Easter in Acts 12:4 just because today's society dropped how they used Easter back in the KJV Bible and more importantly, back in Tyndale's English Bible & Martin Luther's German Bible for why the people, not even the Puritans, of KJV times did not make an uproar about it then..
Hark,
As for Luke 22:1, this verse says DUB was approaching, then in 22:7 the day of DUB came.
These don't specify the day clearly, but verse 7 coincides with Mt 26:17 which says Te Prote
Τῇ δὲ πρώτῃ τῶν ἀζύμων προσῆλθον οἱ μαθηταὶ τῷ Ἰησοῦ λέγοντες αὐτῷ Ποῦ θέλεις ἑτοιμάσωμέν σοι φαγεῖν τὸ πάσχα
τη δε πρωτη is the Dative Form of the Protos πρωτοσ.
This prote, protos means 2 days before the DUB, because Jews couldn't perfectly hurry up
the hiding of the Leavens before the DUB. Therefore 2 days before DUB are the days of preparation hiding the Leavens. One day is the Passover and therefore it doesn't have to be mentioned as the Prote, but one day before Passover was called Prote or Protos.
Then we can solve the puzzle. On the Protos, one day before Passover, Disciples prepared
the Last Supper, and when the evening came, it was the evening of Passover and they had the supper. Lord Jesus was arrested in that night and in the morning He was sentenced to death, on the same day by Jewish Calendar, which was Passover. The Passover Lamb was slaughtered in the afternoon of the same day as Jesus was hung on the Cross, around the time when Jesus cried " Tetelestai"
So, Passover is not always used to represent the whole Feast period of DUB.
Rather, as we see in Luke 22:1, 7, Mt 26:17, DUB was used often to represent the whole Feast of DUB and Passover.
Strangely, in Acts 12:4, it was already DUB in the previous verse, but it mentioned the delay of Execution after Pascha. This Pascha must be after previously mentioned DUB.
Even this year the Passover is 27th March, then DUB ends on April 3 (Some people claim it is by 4th April), the next day is Easter April 4th.
2021 Feast Dates - The Messianic Light
So, the Easter is often around the end of DUB or right after DUB.
Now, let's imagine that Peter is arrested on the 31st March and it is already in the middle of DUB and the government say they are going to execute him after the Pascha?
Would you imagine that the execution will take place after the Passover? or after the Easter?
If it meant the after the end of DUB, it would have mentioned after the Days of Unleavened Bread because it was already mentioned in the previous verse.
But as we understand Pagan Festival is everywhere in the world and they celebrate Easter as if it is the Resurrection Day of Jesus. Likewise, even at the time of Acts 12:4, Ishtar Festival was everywhere in the Middle East and it was almost mixed with DUB or meant the end of DUB, then wouldn't it be called as Pascha because Assyrians called it Pasahu, Chaldeans called it Pischa, etc?
As we can read thru the facts that Tyndale translated Pascha into Ester, throughout the ages and centuries, the paganism surrounding Easter, Ishtar, Astarte, Asherah Artemis have been overwhelming in the spring festivals.
I would rather presume KJV translators dug into quite deep on this matter.
Thanks
Eliyahu