Also if your building a "military" type branche the Navy seals/green beret's despite the media fascination have a particularly narrow job description in the military scheme of things with specific teams for specific jobs for example the Navy seal and Army special forces underwater warfare teams dont train much for counter terrrorism.. thats a seperate team, and again a seperate team for unconventional warfare, or special recon teams even direct support teams to support other military units in combat. despite media portraial they are each highly specialized teams.
You will want a more general elite military unit like the Army Rangers, Marine Force Recon ,Marine Division recon,Germanies Fallschrimjagers, or UK's Parachute regiment. these Elite fighting units are more of the jack of all trades that would better fit many more roles in fact it is from these elite units that you get your Seal,Army Special Forces,German Kommando Spezialkrafte and Britans SAS. hope that helps you get a direction for some reserch for sci fi military unit.