1)
Why does it say "Ahalelah [Hashem]" and "Azamrah [lEi'lokai "?
1.
Radak: I will make known in public.
2.
Malbim: The former is for life, and the latter is for what Hashem gave to me above life. Zemer is greater than Hilul. "Hashem" hints to general Hashgachah; He causes everything to exist. "Elokai" refers to Hashgachah Pratis on him.
2)
What is "b'Odi"?
1.
Rashi: As long as I am alive.
