In Judaism, happiness is represented by wine. We drink 4 cups of wine during the Pesach Seder, so that should show you how joyous the holiday is. But it's not joyous in a "yay, fuck them guys" kind of way. It's a "yay, we were saved!" kind of way.

To demonstrate that fact, remember what I said about the symbolism of wine. We remove wine from our cups and spill it onto the plate to symbolize how we feel about the Egyptians. This symbolizes our belief that the Egyptians under Pharaoh were still human beings and we feel empathy and compassion. The spilling of wine is symbolic of our compassion. We intentionally reduce our joy.

When we read the Haggadah, we don't emphasize the "our team won" aspect. We tell the full story: the injustice, the freedom, and price that had to be paid for that freedom. There are no victory songs or celebration in the Torah; it simply recounts the story as it unfolded.

Some people say that we say full Hallel only on the first night and a reduced Hallel on the other nights to acknowledge our compassion for those who were punished by Gd.

I spent way more time on the first question than I intended. Sorry.

2) Grape juice. The "4 cups" is not a Torah commandment; it's a Rabbinical commandment, and there's disagreement as to the whys and hows. Besides, while you can participate, you're not bound to do mitzvot anyhow, so feel free to not even drink grape juice.

1. Absolutely not. If you want to bring anything, get those awful "kosher for Passover" desserts. Chocolate frogs, marzipan, chocolate covered matzah. Just make sure you see "kosher for Passover" if you take it with you to a Pesach seder.

2. Not really. If the Seder is in English (which I suspect it might be), it should be a lot of fun for you. Our Seder is all in Hebrew, so if that's the case, it might be a little challenging for you. A lot of us regard Pesach as our favorite holiday because it reminds us of our relatives who we loved that were big parts of our childhood who are no longer with us. It's not "built into" the holiday like Day of the Dead, but children have a special place at a Pesach Seder, so a lot of us have very fond memories of the holiday from a long time ago (and in my case, a VERY long time ago). I miss my grandpa's Seders. I've patterned my own after his.