Well, I'm going to tell you which characters have achieved which military ranks in the whole range of FMA =D Hopefully, you'll understand this.
These are only the ranks which Arakawa-sensei showed in the anime, though. For example, I won't put "Major" for Roy. And if I can't remember/don't know a character's first name, I won't put it. [my stupidity is rubbing off -_-;] This is ONLY from the anime - don't want to spoil it for those of you who haven't seen the movie =D
Roy Mustang: Lieutenant Colonel, Colonel, Major
Riza Hawkeye: Second Lieutenant, First Lieutenant
Basque Graun: Brigadier General
Frank Archer: Lieutenant Colonel, Colonel
Maes Hughes: Major, Lieutenant Colonel, Brigadier General
Heymans Breda: Second Lieutenant
Jean Havoc: Second Lieutenant
Vato Falman: Warrant Officer
Alex Louis Armstrong: Major
Kain Fuery: Sergeant Major
Maria Ross: Second Lieutenant
Denny Brosche - Sergeant
If I'm missing anyone, go ahead and tell me. I hope this is beneficial to you in one way or the other!