Awesome looking group you have there.
The belt is Russell Manufacturing Co. 1942, a huge contractor for U.S. web gear, they also made belts for the U.S. in WW1...I have several WW1 items and a group of the same pistol belts dated from 1940 to 1945, all made by Russell.
The holster, Boyt Harness and Leather Co. A common leather and web gear maker of WW2...the holster will turn color with age and sometimes the soldier would apply oil to darken the leather. In my collection there is a lot of Boyt manufactured gear...on the M1928 haversack you will find three different styles of Boyt markings...I have all three.
The Canteen carrier, Shane Mfg. is another contractor who made U.S. web gear...I have several pieces made by this maker, including shovel carriers, and canteen pouches.
I have seen the B.A.B. Co. maker several times on original pouches...it seems they only made first aid pouches...haven't seen their mark on other items though.
What are they makers and dates on the canteen/cup? Some of the makers are quite scarce, especially the Belgium made items.
Nice group of 100% original WW2 gear you have there!!!!!!!