1)
What is the grammatical form of "Yehalech"?
1.
Radak: It is Po'el Omed (the action applies only to the subject). There is a Dagesh in the middle letter of the root.
2)
What does "b'Chukosai Yehalech" encompass?
1.
Radak: It is the Klal, in addition to the particular Mitzvos listed.
2.
Malbim: It is Mitzvos Bein Adam la'Makom; "Mishpatai" are Bein Adam l'Chavero. He is a Tzadik in deed, in addition to a nature prepared to be a Tzadik. It is proper that he live!