Can’t “4” be read in two ways:
4-Money, it was hard to find.
The “it” could be considered as a pronoun replacing “money”.
It could also be considered a “prop it”.
Consider:
The policeman. it was easy to bribe.
(Meaning: It was easy to bribe the policeman.)
The object is fronted in this case, as in:
John, I talked to.
(Meaning: I talked to John.)