Is it important to realize the stain of sin and effects of original sin were removed from Her soul and flesh?

Nothing was removed. They were never there in the first place.

That is correct. Mary because she was to be the mother of the Christ, was conceived without Original Sin, and never sinned in her lifetime,

So the internal temptors were not present in Mary's flesh or soul nor Jesus' flesh or soul prior to their conception. They could not sin, they could not make the choice of good or evil. It was not part of their DNA. This allowed them to bypass dying before ascension. The host, Jesus, brought to earth by the ark of the new covenant, Mary and the Church and Spirit, allows mankind to achieve eternal life of the flesh and soul in heaven.

Peace always,
Stephen

God’s temple in heaven was opened,
and the ark of his covenant could be seen in the temple.

A great sign appeared in the sky, a woman clothed with the sun,
with the moon under her feet,
and on her head a crown of twelve stars.
She was with child and wailed aloud in pain as she labored to give birth.
Then another sign appeared in the sky;
it was a huge red dragon, with seven heads and ten horns,
and on its heads were seven diadems.
Its tail swept away a third of the stars in the sky
and hurled them down to the earth.
Then the dragon stood before the woman about to give birth,
to devour her child when she gave birth.
She gave birth to a son, a male child,
destined to rule all the nations with an iron rod.
Her child was caught up to God and his throne.
The woman herself fled into the desert
where she had a place prepared by God.

Then I heard a loud voice in heaven say:
“Now have salvation and power come,
and the Kingdom of our God
and the authority of his Anointed.”

Peace always,
Stephen

It is most commonly accepted that Mary, wanting to follow in the steps of Her son Jesus, did die and was immediately assumed.

The Church has never said definitively, but the major of theologians believe this to be the case.