Gino,

You got something wrong:

RE  40 days after the resurrection

You forgot to consider the following:

I Corinthians 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:

  8 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.

I Corinthians 15:20 But now is Christ risen from the dead, and become the firstfruits of them that slept.

  23 But every man in his own order: Christ the firstfruits; afterward they that are Christ’s at his coming.

That year Jesus must have risen from the dead on the feast of firstfruits.

He did fulfill all four spring feasts that year: passover, unleavened bread, and firstfruits; then he also sent the Holy Ghost on pentecost.