For the rifle, I'd pick two: The rifleman would get an M16 type rifle (M4, M16, whatever...configurations would vary by intended use) with the 4 position fire selector that was stolen and marketed by DPMS, but it would not be made by DPMS. I'd select Colt or Bushmaster to make them. Probably Bushmaster.
The SAW would be a 3 barrelled version of the XM-214 minigun in 5.56 nato, with a reduced rate of fire and designed to be light enough, with low enough recoil, that it can be handled by the squad's Heavy Weapons Guy without difficulty.
Pistols: Stick with the best, screw the rest. A Colt-contracted M1911A2, which would be the designated version of the M1911A1 with a double stack magazine like the Para Ordnance. It would be double action, but not double action only, and it would be required to maintain the linear trigger of a 1911, and not the suck-ass pivoting trigger of the Para LDA design.
But I'd really like to issue the Zorg Industries ZF-1 if I could procure them in adequate quantities.
CJ