This is my first post so please be gentle
In Green’s Language and History in the early Germanic world, he discusses different aspects that may explain the Easter/paschal anomaly:
One is the Edict of Toleration, before which saw Christian translators trying to stay clear of heavily pagan-related words within their own vocab; one is obviously the need to borrow words to explain the concept; Rolling on from that is the later use of terms which had pagan meanings but could be appropriated, or expanded, by Christianity to explain the new meanings making them more accessible to the newly converted; one is the lateness of the conversion of England in relation to the Christian vocabulary; and a final thing may have been the new approach in England of converting from the top down.
The celebration of the Pagan Goddess, the name of which is possibly related to the dawn, during a time that is probably related to the Spring, or more likely the beginning of Summer (or even both: the dawning of the summer!), most likely transferred well to the idea of the resurrection, rebirth, etc. Despite the use of the pagan term, the festival itself does appear to have been fully Christianised making any name change moot; although such things as the Easter bunny and Easter eggs would seem to be Spring-related, they easily mesh with the end of fasting for lent (everyone ate their eggs on pancake day and a tasty rabbit would have been a relief from all the fish!)
Of course, there may not be an Easter anomaly, there are countries that use terms different to both Easter and Paschal, suggesting that they too may have had relatable words within their vocabularies already that could be appropriated. Maybe the anomaly only looks like one because of the spread of the English!
Apologies if none of that makes sense - but it did in my head