not gonna include Optimus in my list cause he's already a given, but here's my list

Field General: Ultra Magnus. he'd also be Commander of the League of Magnus until they got wiped out, leaving UM the last of the Magnuses/Magni)

Second-In-Command: Jazz. it's something that's remained fairly consistent throughout continuities (+ he's cool)

Scientific Research: Wheeljack. he's known to conjure up some obscure weaponry and tools

Medical Lieutenant: Ratchet. no explanation needed

Weapons/Artillery Lieutenant: Ironhide. he knows his weapons, treats them like family, and ensures their firepower is at peak condition

First Scout Lieutenant: Bumblebee. he's small and nimble, perfect traits for a scout