I have read Exodus 12 to refresh my memory and I found nothing associating the date of Passover being calculated by a crescent moon. There was the word month used but unless I read over it never did find the word lunar or moon.
Now when exactly did Easter become part of Christ? I mean this as a literal Biblical instruction. Christ only observed the Passover and even Paul instructs us to continue to observe Passover in ICorinthians 5:7 Purge out therefore the old leaven, that ye may be a new lump, as ye are unleavened. For even Christ our passover is sacrificed for us:
Therefore let us keep the feast, not with old leaven, neither with the leaven of malice and wickedness; but with the unleavened bread of sincerity and truth.
See Isaiah 1.14--"Your new moons and your appointed feasts my soul hateth..."--the lunar calendar was taken for granted.