Parshas VaYeitzei:Hosafos to Ma'ariv when Davening Early: Part 2

To answer why one would say Ya'aleh V'Yavo even when davening early, the Mishnas Ya'avetz(Siman 2) has an interesting chiddush. I also found this idea in the Shut Mishnah Halachos. The halacha is that if you forget ya'aleh v'yavo at night you don'trepeat shemoneh esrei because we are not m'kadeish the chodesh at night and really one does not need to say ya'aleh v'yavo at night. However, why then do we see it? The Mishnas Ya'avetz says that we say it in reference to the next day which has kedushas Rosh Chodesh. It comes out that even when we daven ma'ariv after nightfall we are saying ya'aleh v'yavo because of the next day. Therefore, what difference does it make if we say it before tzais or after tzais-it is not a tefilla dependent on the night.

Regarding Al HaNisim, I saw in the Rivivos Ephraim that Rav Moshe held if one says Al HaNisim during mincha before Chanuka it is not a hefsek. The reason is that erev chanuka is also the z'man of commemorating the neis of winning the war. If this is so, then kal v'choomer one who davens ma'ariv early could say Al HaNisim. The Rivios Ephraim also quotes Rav Ovadiah Yosef who says this as well.

For V'sein Tal U'Matar I didn't find a clear reason why you would say it. The Ishei Yisroel just say swe do and he brings to sources but it is not clear why.