Wonderful topic Suhana!
I would like to take a wild guess here about the "auna bauna" confusion...
If anyone saw Jaan-E-Man, you would know that Anupam Kher played a dwarf in the film. He was referred to as "bauna". So, I am assuming that auna-bauna probably mean "small-big" as in choti badi baatein.
In the Maachis song, it may have just meant that the charkha can work in a big-small whatever place. And for the JBJ Hollywood song, I don't remember the entire song. But since it is "auna bauna hi sahi, dil ka kona hi sahi".. it may mean whatever place there is, will be okay... even a corner of your heart.
This is totally a guess in connection to the dwarf word. Someone else who is confident about this, please throw light on this.