It's been a while since I read through Shannon's papers, but I will do it again (though probably not tonight).
As I recall, his work in the 1940's was oriented to communications, the mathematics of communications. That was the "state of the art". The term "information" was coined for success and "entropy" for failure. The second term (as I recall) was coined with his permission and has led to much confusion because of its usage in other contexts.
No, "entropy" was used because the formula for information was the negative of the formula derived by Boltzmann for thermodynamic entropy. Someone (I think Hamming told me that it was von Neumann) suggested jokingly that Shannon should call information "entropy" because no one would understand what he meant.