The problem I see using oven-off or any degreasing formula is that because you cannot see very far inside the intake, you cannot insure that you get it all, and steam cleaning will better insure all is clean.

If unless there are clumps that are hardened, which I doubt, getting some of this residue into the firing chamber while running probably wouldn't be detrimental, certainly not a good thing but I wouldn't worry about it. The chief thing I see here is intake restriction and will very likely suffer in performance!