The kanji above the chevron markings only says "Rank Emblem". Doesn't tell you what the ranks are. There is a book that shows the insignia for different ranks of officers for both Fed and Zeon, but there are no established rank markings for MS. Only uniforms.
The Griffon emblem belongs to the Principality of Zeon Defense Platoon, basically their homeland security squad under Giren's command.
The yellow emblem belongs to the Mobile Assault Fleet, which is under Kishiria's command. You can see it on the Black Tri-Stars suits.