I researched this a bit and still wasn't quite clear.

As a Platinum, do I have access to Flagship lounges (and any Admirals Club) when flying to Central America? Even when flying on a coach ticket?

A Citi Executive World Elite Mastercard with Admirals Club membership does NOT grant Flagship access, correct?

The only time Platinum status grants me Admirals club access is when I am flying on a domestic first class ticket?