In the early 80s the Coast Guard went to the rank of Commodore just as the Navy did for one star admirals. Shortly thereafter the issue was settled by giving lower half rear admirals one star and upper half rear admirals two stars. At that time the Coast Guard did the same thing for their flag officers.
One thing that I did not see mentioned was the "flag status" of a commodore. A commodore did not get his flag as an admniral did, but instead flew a pendant from his flagship indicating the squadron commander (the commodore). That is still the case, a captain of the (usually) biggest combatant ship and who had seciority in rank is designated the squadron CO, or commodore. this can be for as few as 2 ships, or as many as are in the squadron.
However today with the profusion of admirals there are rarely 3 or more ships assigned together that do not have an admiral assigned.