Catholics believe in the assumption, vs. the Orthodox belief in the dormation, or falling asleep. In a nutshell, the assumption is Catholic dogma, while the dormation is more an Orthodox tradition rather than dogma. The Catholic Church doesn't go into details regarding the specifics of the assumption other than Mary's body and soul were assumed into heaven, while according to the Orthodox dormation Marry died, was dead for three days like Jesus was, resurrected, and then assumed into heaven.
Many thanks to both you and Salvation. However I believe you’ve made a mistake on the Orthodox view. Mary wasn’t resurrected but is piously believed to have been assumed into heaven (in a glorified body).
As to the last supper it was agreed to for the Church as a whole for clearly a millennia and a half to be the physical body and blood of Christ. Columbus discovered America before the first Protestant discovered it might have been allegory.
As to Christ having “siblings”, these were either cousins or possibly other children from Joseph and a late wife. Please remember that Joseph was most likely 40-60 years older than Mary and was more her protector than a spouse in the modern sense.
These last few points aren’t directed towards you, but rather to supply hopefully more clarification to what you and Salvation have rightly stated in this discussion.