The Lord chose to rise from the dead on First-fruits, the third day of the Passover Feast. Why? Could it be because that's the Day He intends to resurrect His Bride, the Church?
The Apostle Paul appears to think so!
"But now Christ is risen from the dead, and has become the first-fruits of those who have fallen asleep. For since by man came death, by Man also came the resurrection of the dead. For as in Adam all die, even so in Christ all shall be made alive. But each one in his own order: Christ the first-fruits, afterward those who are Christ’s at His coming. Then comes the end..." [1Cor.15:20-24]
The above verse is telling us that the Lord Jesus Christ rose from the dead on First-fruits to become the very embodiment of that Day! In other words Jesus Christ Himself IS the Day of First-fruits, and as a consequence the resurrection of the dead!
This is why the Lord said:
"I am the resurrection and the life." [John 11:25]
"...those who are Christ's at His coming" are those of us who now have the first-fruits of the Spirit flowing into us from the Lord Jesus Christ. Without these first-fruits the Lord won't be able to redeem our bodies when He comes.
This is why the Apostle Paul said:
"...we also who have the first-fruits of the Spirit, even we ourselves groan within ourselves, eagerly waiting for the adoption, the redemption of our body." [Rom.8:23]
Kerrie L. French, the owner of the Creator's Calendar website, hasn't published the Spring 2016 - Winter 2017 Creator's Calendar yet. I have been in contact with her. And she said she'll be publishing the Creator's Calendar on her website very soon. She also confirmed that First-fruits, on the Creators Calendar, does indeed fall on the 7th of May 2016!