1)
Why does it mention the Shofar?
1.
Radak: This includes also trumpets 1 .
2.
Malbim: There are two kinds of praise. (a) B'Kadsho, bi'Gevurosav (for conduct above nature) will be in the future, when Yisrael will be Am Kerovo. They will praise with drums and dance, to hint that He is at the head of the dance (in the middle). It will also be with the Shofar, to shows the fear that they should have from His grandeur, and with harp and lyre, which show Simchah. (b) Refer to 150:4:3:1.
1
Some verses explicitly mention both of them, e.g. 98:6! Shabbos 36a says that the names Shofar and Chatzotzeros switched. It does not say that "Shofar" includes both of them! (PF)