Storm Captain and Command Missions

I was told that in order to go from First Storm Lieutenant to Storm Captain, I have to do five (or maybe it was six) different command missions before a flagged mission appears.

Does it matter which five or six that I do? Could I just do the lowest five dungeons and get the flagged mission? I heard that the squadron kinda suck in dungeons so I do not want it to be too hard.

"Once 5 different Command Missions have been completed, Flagged Mission: Sapper Strike becomes available."

I also just ran the 5 lowest level duties I could do. Quick and easy.
I recommend running as a class without cast bars since no matter who has aggro, attacks/mechanics that target a random player will always target the only actual player there: you.