Celebrating Passover with family is not speculation. It is a matter of historic fact that Passover was celebrated with family.
Now his parents went to Jerusalem every year at the feast of the Passover. And when he was twelve years old, they went up according to custom; and when the feast was ended, as they were returning, the boy Jesus stayed behind in Jerusalem. His parents did not know it, but supposing him to be in the company they went a day’s journey, and they sought him among their kinsfolk and acquaintances; (Luke 2:41-44)
Extended family and sometimes whole villages traveled together to Jerusalem for the Passover. The text above shows that Mary and Joseph’s family and friends were with them. How Passover was celebrated is common knowledge, not speculation.
Pilgrimages to Jerusalem to attend the Passover (Luke 2:41), the Feast of Tabernacles (John 7:2), and other major religious events were the social highlights of the villager’s year. Religious obligations could be fulfilled while leaving enough time to shop, to see family and old friend, and to pass on to the young the importance of their cultural heritage.
- Manners and Customs in the Bible: An Illustrated Guide to Daily Life in Bible Times, Hendrickson Publishers, 2006, Victor H. Matthews
God commanded the first Passover to be eaten by the household or multiple households together and that is the way it was celebrated ever since, even to this very day. It is almost impossible for the Apostles and Jesus to have been alone and this renders the OP’s premise that the Eucharist was only for Apostles because only the Apostles were there highly unlikely at best.
-Tim-