Why this works:

Noob's (and Tanya) throw has a glitch called OTG, which guarantees you a combo (in this case, the Death From Above special move)

Smoke's throw is able to be comboed infinitely. This is because his Down 1 stuns the opponent long enough to grab them again when the opponent is close to the wall. The AI at low difficulties however, tends to let you grab them regardless of where you're at on the stage.

Why this doesn't work (well):

Noob nor Smoke don't have combos to fight Onaga with. While it definitely IS possible to take on Onaga with Noob-Smoke, it is highly inconsistent. I recommend using either Scorpion or Sub-Zero (must be playing from player 2 if using Sub-Zero) to fight Onaga.