Is the "lo" necessary here? I'm not sure I understand the grammatical reason for it.
Presumably because it's with that specific sugar, and not all or any sugar in the world.
Defined as blend, mix, etc, but didn't except blend. Be'
Is 'col' instead of 'con lo' wrong here because 'zucchero' starts with 'z'?
Le donne sono nello zucchero... accanto alle mosche.