Two shiurim for Adar Rishon and parshat Ki Tisa

I've been listening to some of the shiurim at YU Torah. Here are my thoughts / reactions to two of them.

1. Understanding the Chet Ha'Egel -- 5 minutes
Rabbi Herschel Schachter

Two interesting takeaways from this five minute shiur.
#1: According to Ramban, a mitzvah deOraysa to hear the chet ha'egel. Such that like Zachor, hearing Ki Tisa is deOraysa. (1:40 minute mark)
#2: Bamidbar Rabba is late. Things Rashi cites from Rav Moshe haDarshan are found in Bamidbar Rabba. (3:30 minute mark)
2.
Simcha in Adar Rishon -- 10 minutes
Rabbi Aryeh Leibowitz:

4 minute mark:
Chasam Sofer: Shulchan Aruch doesn't say mishenichnas Adar marbim beSimcha because no practical ramifications. Meanwhile miShenichnas av memaatin beSimcha has practical ramifications, e.g. scheduling a wedding.
He asks that this is a bit difficult: The gemara says (Taanis 29a-b):
משנכנס אב ממעטין בשמחה כו':  אמר רב יהודה בריה דרב שמואל בר שילת משמיה דרב כשם שמשנכנס אב ממעטין בשמחה כך משנכנס אדר מרבין בשמחה אמר רב פפא הלכך בר ישראל דאית ליה דינא בהדי נכרי לישתמיט מיניה
So the gemara gives a practical ramification, to schedule a court case during that time.

I think that not every question is a strong question, just because one can ask it.

There is a difference between an *halachic* nafka mina and a practical good-advice nafka mina, operating under the assumption of astrological impact on our lives. Rav Papa was giving a good idea, not paskening that one must schedule a court case in such a way. It is incorrect to then ask, "of course there is a *halachic* ramification!"

But presenting the question and leaving it like that makes it seem like the Chasam Sofer didn't have such a great answer.

So too regarding the next answer that others proffer, that ain mazal leYisrael. He asks, but the Shulchan Aruch still says mishenichnas av memaatin besimcha, so if it is all dependent in mazal, then it should either say one or the other.

I also don't see this as a great difficulty. When saying משנכנס אב ממעטין בשמחה, whether it is taluy in mazal or not, the beis hamikdash was destroyed then, and this is the phrase in the Mishna that introduces practical Halachic ramifications which are lehalacha, whether or not there is mazal.

Namely, the Mishna says:
משנכנס אב ממעטין בשמחה שבת שחל ט' באב להיות בתוכה אסורין מלספר ומלכבס ובחמישי מותרין מפני כבוד השבת ערב תשעה באב לא יאכל אדם שני תבשילין לא יאכל בשר ולא ישתה יין רשב"ג אומר ישנה רבי יהודה מחייב בכפיית המיטה ולא הודו לו חכמים:

So it is going to drag along that iconic phrase even though the Mazal itself isn't paskened.

Alternatively, what these people are suggesting is that we hold like the Mishna but not like the extra statement of Rav. The Mishna is halachic. Rav and Rav Pappa are talking about mazal, extending the idea of the Mishna.