A non frum family member wants to come to us for the 2nd Seder. Is that a problem?
ב"ה Shalom The invitation itself is a great mitzvah of having people distant from torah and Mitzvot to experience an authentic and kosher seder. By doing so you are going in the footsteps of Avraham Avinu and Aharon Hacohen who performed the great mitzvah of bringing people closer to Torah and belief in Hashem. If your question was in regard to the possibility of them travelling to you by car other means prohibited on Shabbat and Yom tov, the question is if we are now causing them to do an aveira, "Lifnei Iver" ,by inviting them. I myself had this question many years ago in regard to a guest who did not keep Shabbat. I asked the Gaon, Rav Avraha, Shapira zt"l, the former Chief Rabbi of Israel, and he told me to make accommodations for the guest for the entire Shabbat. Once I have done that, he said, the decisions made by the guest as to where he or she is for the rest of Shabbat are his choice. The same ruling was given by Rav Shlom Zalman Oirbach zt"l, from Yerushalayim and he even added that the host doesn’t need to ask how the guest is arriving. This is also said in the name of Yakov Kaminetzky zt"l. (See (,מנחת שלמה ח"ב, סי' ד, אותי, רבבות אפרים ז,תב, אמת ליעקב, חו"מ סי' תכג, הערה 27 עמ' תס,תשובות והנהגות כרך א', שנ"ח, שואלין ודורשין ח"ב, סי' ג) ) Therefore, in answer to your question. You should earnestly make accommodations for your guest to stay for the entire 2 days of Yom tov. the rest is up to him or her. As far as touching of the wine by your guest, you should use "Mevushal" wines and grape juice and avoid problems. All the best Happy Pessach Chag Same'ach