It's pretty interesting thus far, I just have some background/story questions. Course feel free to avoid spoilers.
First off, you are using military ranks for the characters. I'm assuming since they're special forces they may all be from different branches of the military, however I see a lot of Marine references. Is the marine corps your primary inspiration?
Since this is the Sonic Wave continuity, what is some of the backstory that leads up to the situation? In Archie Geoffrey is only a few years older than Sonic and co, so during the Great War he'd be a mere child. How is this different in your universe?
How tall are your Mobians? Sonic's official Height is 3'3''. This averages Mobians at 3-4 feet tall. This also explains why Sonic usually only comes up about halfway on Eggman. Are you making your mobians taller or using the normal heights?
well to answer your first question. given their designated as a "black ops" unit, i think its safe to assume they are a sort of de facto "fifth branch" of the GUN forces. this is actually advantageous as it makes team echelon an extremely flexible fighting force capable of rapid action and deployment while other squadrons like spider trope and team paladin are bogged down in bureaucracy(shadow did bring up a couple of times how much he doesn't like GUN protocol) and are directly answerable to the president. essentially the UF's version of the secret service or "section 9" and as such, Commander Tower and Hugo Brass are very distrusting of them for obvious reasons.
also, what makes my Sonic WAVE continuity different from the main timeline is of course this great war lasted considerably longer than 5 years for reasons I have yet to explain, but one of the factors has to be the United Federation forming before the onset as was revealed by the narrator.
also different is instead of collaborating, Naugus and Robotnik/Dr.Eggman are too busy fighting amongst each other for either of them to attempt a coup de etat (Yet) but both are aiding The kingdom of acorn with technology and magic..if only to divert attention away from their own agendas.
sub-human overlanders also don't exist in this timeline, only humans and mobians.
lastly, mobian heights are difficult to gauge sense they vary from race to race. but i would have to say mobians can be around 3"3 as Sonics official height all the way up to human height in this timeline. so I would say Geoffery St. John is about up to Lt. Allen's upper chest at most (5"7).
and that's as far as I'm going to go without spoiling anything.