there would be no reason for herod...who had no respect for christianity...to have waited until after the christian celebration of jesus' resurrection...
it is clear that herod was waiting until the end of the jewish feast of unleavened bread...also called passover...and that the 'pascha' in this passage is referring to that feast...not a christian feast anachronistically called 'Easter...
"hats off rachel,,,,",,,,,that is Herod(Jewish/non-christian),,,,,who cut off James(a christian) head,,,,and seeing it pleased the (Jews/non Christian) he was about do cut off peters(christian) head also,,,,,,but he(herod/jewish non christian) stopped to celebrate "easter",,,,as you point out the only one time the word translated Easter in the bible is being celebrated by a Jewish non christian,,,,to rachel,,,
to the others,,,, now the works of eusebius,,are not the only works that should be researched on this matter,,many of the early church members reflected on this very matter,,,,,"Eucharist",,,,in the fragments of irenious is the recollection of this (as it was celebrated by the churches in rome one way and in aisa another),,,polycarp traveled to rome and argued the very point stating the way that john and the other apostles celebrated it,,(?),,,,that is they did not "bend the knee",,,or bow down(?),,,,in the end they yielded to polycarp seeing he was the only surviving church member who had witnessed the apostles teaching.
Polycarp of Smyrna: The Second Century Heretic Fighter here is an interesting article,,,,"i am not a member of c.o.g. organization",,,,,i am christian.. but i give this to help you with your own private research. read it all if you like but if you scroll down to "Easter",(3/4 down) there are mentioned the letters about the churches divisions on the same matter "Easter" as to how it should be viewed. it was not changed to sunday for a hundred years this meeting. but as ireanius pointed our in the fragments some celebrated it one way some another,,some one day,some seven,some every day of the year. i every-time i eat and drink,,,but be compelled to honer this after your own research, yesterday was the lords day to me,tomorrow is the lords day to me,,today is the lords day to me,,,,,,,,,i ask blessing for the bread that was broken,,and the cup that was poured out,,,