Squad MG is the LMG. Browning M2 is a battalion level weapon.
Common mistake on this thread. You now have three different rifle calibers.
Well, I gave the Enfield a shout out since it was probably the ultimate expression of the bolt action rifle.
The Garand was simply the best personal weapon of the war, hands down. Sub guns in the American calibers were simply God-Awful, but sub guns are too handy to ignore.
The U.S. also actually USED three different/pistol rifle calibers during the war in the 30-06, the .30 carbine, and the .45. There were also .38 revolvers and even some 9mm.
Supply chain in this sort of set up are always going to be a POS unless you adopt all of a single country's weapons (and frequently not even then, as the above example indicates).
If a logical set up that would allow for a simple supply chain that might have been mentioned in the OP. However it seemed that the OP was for a mix and match.
If you want, you can just replace all the non U.S. systems with the G.I. versions. I didn't, however, understand that was being looked for since the OP states:
...could pick and choose from all the various armies equipment, how would I equip my WWII army
