1)
Why does he rejoice over Hashem's Edus?
1.
Radak: It is when he sees wondrous Chachmah in them, and straight and righteous matters.
2.
Malbim: Edus are tales in the Torah that testify about Hashem's Hashgachah, reward and punishment. Pekudim are Mitzvos of action that teach about these in particular, e.g. Matzah, Maror, Sukah and [Kedushas] and Bechor. Each teaches about a particular detail called Orach. He found in them all wealth, dearness and Segulah of Emunah that he gathered in his Nefesh.
2)
What is "k'Al Kol Hon"?
1.
Radak: It is like one who found great wealth.
2.
Malbim: Derech is the big [fixed] path. Orchos are small paths [that branch off the big road].
