"On the first day of Unleavened Bread, when the Passover lamb is sacrificed, his disciples said to him, "Where do you want us to go and make the preparations for you to eat the Passover?" So he sent two of his disciples, saying to them, "Go into the city, and a man carrying a jar of water will meet you; follow him, and wherever he enters, say to the owner of the house, 'The Teacher asks, Where is my guest room where I may eat the Passover with my disciples?' He will show you a large room upstairs, furnished and ready. Make preparations for us there." So the disciples set out and went to the city, and found everything as he had told them; and they prepared the Passover meal. (Mark 14:12-16)"
That meal was the last supper.
I understand that you don't believe that Judaism + Jesus = Christianity, because you don't wish to associate your faith with our "heretical" one. The problem with this is that Jesus and the disciples were Jewish and did follow nearly all of the laws of Moses. It was in the year 49 that they had talks about whether or not these rules should be followed by the Gentile converts to their faith, but the non Gentile Christians were still following the laws. Christianity came from people who were Jewish. They accepted converts, yes, but so did Judaism. Although you don't believe in intermarriage, wasn't Ruth not Jewish? And Esther married outside of the faith as well.
As far as saying that we weren't enslaved in Egypt and we didn't wander the desert, we believe that is part of our Church as well. You may disagree, but you don't know Christian teachings if you say that it was not our shared history.
I think that you dismiss Christianity as heretical, and therefore, when you ask where you have misspoken about Christian beliefs, it lies in the things you've dismissed that we believe as true.
As far as Christmas and Chanukah, I'm going to celebrate both as family gatherings. They'll learn both sides. I don't care if my kids believe that Jesus is the messiah, but I'll teach them that my family believes in Jesus, and that Christmas celebrates his birth. But I will celebrate the two side by side, despite your objections that they are incompatible.
I know many people who were raised in interfaith families. They all grew up celebrating both. One person raised both now is Orthodox and still celebrates Christmas with her father and her fully Jewish children.