As far as I know, there's not much earth-linked representation specifically for the Rebels. Their pilots uniforms are a mix-match of real-life flight gear with sci-fi additions.
The uniforms, as far as I know, were to represent a less well backed group financially... Thus the non-matching RFT uniform's... There was also an implied "age gap" in Rebel soldiers as well, with some being noticeably old while others were extremely young. A "hodge podge" military force of sorts.
Rebel forces have been said to represent most any rebelling/smaller military force from Earth's history though. From French resistance or Viet Cong, to Continental Soldiers of the American Revolution. There's a uniform quality there, but obviously there's militias and multiple "allies" mixed in there too.
Like at the Home One briefing, it looks like a pre-D-Day invasion staff meeting. Tibrian militia, Dresellian Militia, Mon-Calamari Navy, Alliance (Main military force) Fleet and Spec. Forces personnel...
There's the main military represented there (The Alliance personnel like the commandos, Spec. Ops officers, and arguably the Mon Calamari whose uniforms may be Alliance-standard rather than Mon Cal specific), as well as the local militia representatives of 2 species who are there for some reason (Tibrians maybe have a small fleet or sent fighters? Dressellians went to Endor). So, it could be compared to situations in WW2 between the allies, or a meeting of Continenal army/militia prior to a battle with the British.