Your questions are loaded with misunderstanding. The Last Supper and the Crucifixion are inextricably united.
The Last Supper is not the Sacrifice on the Cross
WHEN did Jesus cry out to Abba to remove this cup from Him : before the Supper of before the Cross?
WHEN was the Sin of believers paid for: at the Supper or on the Cross?
WHEN was propitiation made: at the Supper or on the Cross?
WHEN was the Blood of Christ shed for our forgiveness ; at the Supper or on the Cross?
WHEN was the wrath of God appeased : at the Supper or on the Cross?
WHEN was he pierced for our transgressions, When was he crushed for our iniquities; at the Supper or on the Cross?
WHEN did the Lord lay on him the iniquity of us all; at the Supper or on the Cross?
WHEN was the Lord’s will to crush him and cause him to suffer, and though the Lord makes his life an offering for sin; at the Supper or on the Cross?
WHEN did God make Him who had no sin to be sin for us, so that in Him we might become the righteousness of God;at the Supper or on the Cross?
At what "event " did these thing happen?
You see, the Last Supper is the first Mass. And the Mass is our Passover. In order to understand the New Testament Mass, you must understand the Old Testament Passover.
1. In the Old Testament,
a. The Passover Lamb was killed and
b. The Passover Lamb was eaten.
Those are not two sacrifices, but one. The Passover Lamb was killed in order that it might be eaten.
2. The same in the New Testament.
a. Jesus Christ is the Lamb of God.
The next day John seeth Jesus coming unto him, and saith, Behold the Lamb of God, which taketh away the sin of the world.
b. Jesus Christ is also our Passover, sacrificed for us.
1 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:
c. He is sacrificed for us in order that He may be eaten:
King James Version (KJV)
57 As the living Father hath sent me, and I live by the Father: so he that eateth me, even he shall live by me.
d. Therefore, Christ released the grace of God from the Cross. But unless you eat of the flesh of the Son of God, you do not apply those graces to your life. And you will die in your sins:
53 Then Jesus said unto them, Verily, verily, I say unto you, Except ye eat the flesh of the Son of man, and drink his blood, ye have no life in you.
e. And finally, the Crucifixion is the Sacrifice of the Mass which we participate in when we eat the Body and Blood of our Lord in the Holy Eucharist.