The bad luck has already come to you if you had met somebody with an empty bucket. The idea with greetings seems to be used for lyrics only.
I've never heard of such a version of the word "воробей" etymplogy . Sometimes people tend to find (or rather to stuff) a sense where there is actually no any. If one can split a word in to two that does not mean that the meaning of the original one and the two splits are identical. For an example if use this word splitting idea we can come to the word "ворожить" meaning "let a thief to live".