Questions

The Mishna in Pesachim (116a) says מזגו לו כוס שני וכאן הבן שואל אביו ואם אין דעת בבן אביו מלמדו מה נשתנה הלילה הזה מכל הלילות.  The Rashbam says (in first peshat) כאן במזיגת כוס שני הבן שואל את אביו אם הוא חכם מה נשתנה עכשיו שמוזגין כוס שני קודם אכילה.  In other words, the pouring of the second cup causes questions and the main question is about the pouring of the cup.  The questions of מה נשתנה of for the child that does not take the initiative and ask questions on his own.  Accordingly, the Rashbam understands the Gemarah (115b) that says when a question is asked by the child it exempts from מה נשתנה at face value for the מה נשתנה is only necessary if no questions have been asked.  

Tosfos takes a different approach.  Tosfos (115b) says even after a child asks a question on his own, there is still a requirement to say the מה נשתנה. In other words, Tosfos understands that there is a takkanah to say the מה נשתנה and that must be said even if other questions have been asked.  It would seem Tosfos holds that Chazal insisted specifically the questions of the מה נשתנה be used. 

That may be because in Tosfos's view the obligation of questions Or Tosfos may not hold that one needs specifically the 4 questions but one's questions but be based upon the mitzvot of the night not other events.  

The Alter Rebbe (473:40) says יִתְעוֹרְרוּ לִשְׁאֹל גַּם כֵּן שְׁאָר הַשְּׁאֵלוֹת: "מַה נִּשְׁתַּנָּה וְכוּ'", לְקַיֵּם לְבָנָיו מַה שֶּׁנֶּאֱמַר: "כִּי יִשְׁאָלְךָ בִנְךָ מָחָר לֵאמֹר מָה הָעֵדֹת וְהַחֻקִּים וְהַמִּשְׁפָּטִים וְגוֹ', וְאָמַרְתָּ לְבִנְךָ עֲבָדִים הָיִינוּ וְכוּ'"  It is part of the mitzvah to have questions and answers at the Seder. Earlier (#14) in discussing karpas he says אֲמִירַת הַהַגָּדָה מִצְוָתָהּ לְאָמְרָהּ דֶּרֶךְ תְּשׁוּבָה עַל שְׁאֵלוֹת שֶׁשְּׁאָלוּהוּ, שֶׁנֶּאֱמַר "כִּי יִשְׁאָלְךָ בִנְךָ וְגוֹ', וְאָמַרְתָּ לְבִנְךָ עֲבָדִים הָיִינוּ וְגוֹ.'  Why does he change the pessukim of the source of the need for questions?  There are two different types of questions that can be asked at the Seder.  One is just bewilderment at the general strangeness of the events that we do and the other type are specifically related to the mitzvot of the night.  The karpas is not related to the mitzvot of the night, it is just something we do to evoke questions about the events of the Exodus.  That is the possuk of the generic עבדים היינו but questions specific to the mitzvot of the night are derived from מָה הָעֵדֹת וְהַחֻקִּים וְהַמִּשְׁפָּטִים.  This is fulfilled by the מה נשתנה but can not be fulfilled by general questions and that may be why Tosfos requires the מה נשתנה to be asked (see Rishimos Shiurim siman 100.)    

The Alter Rebbe (473:43) says וְעִקַּר נֹסַח הַהַגָּדָה שֶׁתִּקְּנוּ חֲכָמִים חוֹבָה עַל הַכֹּל, הוּא מִתְּחִלַּת "עֲבָדִים הָיִינוּ.  There is a precise text that Chazal enacted to said and that is the Haggadah which starts at עבדים היינו.  What about the מה נשתנה?  It would seem although the questions of מה נשתנה are a key part of the Seder, the precise wording of the questions is not part of the takkanah of Haggadah.   

The Rambam says in his seder Haggadah that the second cup is poured before the beginning of Maggid.  In addition, the Rambam (8:2) says the one leading the seder says the מה נשתנה.  This indicates that the Rambam is of the opinion that the questions of מה נשתנה are indeed part of the Haggadah (see also הוספות ללקו"ש חלק ג.)  Accordingly, the Rambam omits the Gemarah on 115b for he holds the מה נשתנה must be said as it is part of the Haggadah.  

Rav Chayim says that one of the differences between the general mitzvah of זכירת יצ"מ and סיפור is that the Haggadah must be said דרך שאלה ותשובה.  It would seem that he understands that is a Bibical difference.  It is clear from the Alter Rebbe that the שאלה is not part of the integral part of the Haggadah text that Chazal enacted but maybe one can suggest he may agree that it is a necessary component of the Haggadah but there is on defined text? 

The Yarech L'Moadim suggests a possibility according to the Shulchan Aruch who holds that one pours the cup of wine before עבדים היינו that he can agree in principle to the opinion of the Rambma that the Haggadah is said over the second cup of wine but he holds the questions of מה נשתנה are not part of the Haggadah.  He quotes from Derech Sicha that Rav Chayim Kanievsky said that in fact only the עבדים היינו has to be said after nightfall, not the questions for the questions are only a means of getting to the answer.  This line of reasoning for sure does not work with the Rav Chayim for the suggestion here is that the questions are not part of the Haggadah.