Q: Is it all right for our parish to host a Seder meal during Holy Week?
A: Um, no. Here’s a quote from the USCCB. This says it better than I can.
What does the Church say about Christians celebrating a Jewish Seder?
A. Many Christians are given the opportunity to participate in a Passover Seder during Holy Week.”This practice can have educational and spiritual value. It is wrong, however, to “baptize” the Seder by ending it with New Testament readings about the Last Supper or, worse, turn it into a prologue to the Eucharist. Such mergings distort both traditions.” Ideally, then, Christians who wish to attend a Passover Seder should do so at the invitation of Jewish friends, families or synagogues that often welcome guests to this important meal. This allows Christians to experience the Seder as a Jewish family liturgy, still deeply meaningful to Jews everywhere. However, in the event that Christians celebrate the Seder alone, the following advice should prove useful:
“When Christians celebrate this sacred feast among themselves, the rites of the haggadah for the Seder should be respected in all their integrity. The Seder . . . should be celebrated in a dignified manner and with sensitivity to those to whom the Seder truly belongs. The primary reason why Christians may celebrate the festival of Passover should be to acknowledge common roots in the history of salvation. Any sense of “restaging” the Last Supper of the Lord Jesus should be avoided…. The rites of the Triduum are the [Church’s] annual memorial of the events of Jesus’ dying and rising.” (God’s Mercy Endures Forever: Guidelines on the Presentation of Jews and Judaism in Catholic Preaching, no. 28)