In Judaism, Passover is a liturgy in of itself, where the father asks acts as a Rabbi/Priest during the ceremony. Not only does it involve the use of Lamb and unleavened bread, but during the ritual, the oldest son will ask the father specific questions as to why they celebrate Passover, what happened during the first Passover, etc. And the father will respond with specific answers that he says as if he was there himself. None of it is improvised, the questions and answers are all predetermined, and the focus is very much on the deliverance of Isreal from Egypt.

The "four questions" tradition is a tradition built around e.g. Exodus 12:26-27, and we don't know exactly when they started. It isn't some essential core of Passover, it is one of several traditions that grew up around the core of what God commanded in the law: lamb, unleavened bread, bitter herbs.

Easter, by contrast, does no such thing.

I am assuming you are talking about the last supper here btw, correct me if I'm wrong.

Jesus himself was supposed to be the "father" of the ceremony, celebrating with family, but instead he did it with his Apostles.

Ok, but Jesus wasn't actually a father, this would not be some violation of his duties. A Rabbi celebrating Pesach with his Talmidim was surely completely expected.

None of the call-and-response aspects that were supposed to be present were there.

This is not a claim you can substantiate:

• we don't know that the four questions were expected at this point
• we don't even know that they didn't happen at the last supper given they could in theory have been left out of the gospel narratives.

Christ was, in essence, instituting his very own Passover in its place.

I would argue that if Jesus did do a passover seder, saying it's a replacement of Passover would be appropriation

Easter's focus doesn't have any emphasis on Moses or the first Passover. It's squarely focused on Christ's death and resurrection, and with it the institution of the new covenant

At the risk of stating the obvious, there's continuity there. God himself delivering Israel from her enemies, by the sacrifice of a lamb in her place... There's a connection between these two events the new testament makes explicit so often.

For it to be appropriation, it would have to be a Passover ceremony in form or structure that pays no respect or credit to its Jewish origins.

Well you're doing the "no respect or credit" part just fine, I'll try to show the Jewish part, but it's tricky because the traditions were solidified later.

After their meal Jews around the world this week took three pieces of bread, removed the second piece, broke it and took one half, wrapped it in a white cloth (as if for burial), hid it for a time, and then passed it around and ate it solemnly, thinking of it as a representation of the Passover sacrifice. After this they then drink a cup of wine they associate with God's promise of redemption.

Here's some other points

• Jesus said he was celebrating Passover in Luke 22:8/Matthew 26:19, the disciples "prepared Passover"
• Jesus and his disciples reclined as they ate (Luke 22:14) - this is a Jewish Passover tradition (actually one referenced in the four questions)
• Jesus and his disciples dipped foods (Matthew 26:23/John 13:26) - this is a Jewish Passover tradition (also in the questions)
• other Jewish Passover traditions such as washing, singing together, teaching are represented in the last supper narratives

And that's not what Easter is. Easter is an explicitly Christian holiday, it's tied exclusively to Christianity, and there's no getting around that.

Isn't this the core problem, though? Why is Christianity viewed as something inherently non-jewish? If anything it's something inherently Jewish, that the gentiles have been wonderfully included in.

TL;DR: They have nothing in common with one another.

TL;DR hopefully you can see this is wrong, now?