Not a jot or tittle was to pass from the Law “until all [was] accomplished.” Most point to Jesus’ “It is finished” as that point.
The context of how the Law even came to be imposed is significant here. The Hebrews had a chance to agree with Moses that it would be impossible for them to keep; but they insisted that it was not and said they would accept the Law, leading to a long long saga that proved Moses was right about that and that they weren’t.
One could make a case for greater freedom after that point, but there’s an excellent observation here that to bring blood in BEFORE it, would at the very BEST be too early.
No — this was a symbol. The Jewish Passover traditions that date almost as far back as gospel times are emphatic about the symbolic nature of the foods partaken of. Church tradition, desirous of control, claimed too much.
A very strong clue is that we are to be spiritually reconciled (confessing our sin to God for foregiveness) before partaking in the ciommunion. We are built up spiritually by partaking in the Remembrance in humility. By the same token, as Paul emphasized in the Corinthian letter, to partake unworthily is to get the opposite out of the communion Remembrance. That state is guilty of the body and blood of Jesus, as in violating the Levitical admonitions.