Always nice seeing other people make attempts at historical recreations of combat units!
I do have a couple of notes if you wish to refine your setup even further, but I will say that you’ve done a great job so far!
Early war marines:
You’re using a lot of of Garands, which I would advice against when representing early war Marines. As a rule (not formal, just observed reality) in the US military the Marines get the latest stuff last, and nowhere is this more prevelent than in the USMC when it comes to the M1 Garand. The Rifle was only formally adopted in Febuary 1941, and it would take until after Guadalcanal in 1942 where they got to fight alongside Army units equiped with the M1 until they actually started pushing for the mass adoption of the weapon, otherwise the few M1s that they already had were almost always issued to garrison units and not combat formations. I would advice you to skim down the use of the M1 (almost all of them, if not all of them, depending on what year you want to represent) in favour of Springfield rifles (squads you designate as “Paramarines” could use the M1941 Johnson Rifle, if you want variaty).
Nice detail about mixing the use of M1928A1 and M50 SMGs though, I would though try and standardize on one type of SMG per squad (even if you as a whole use different SMGs on different squads), to represent the real world logistical attempts on stadardizing maintanance parts (not always possible of course, but it was at least atempted).
The M1919A6 is quite late war, appearing first in 1943, I would caution against using it depending on the time period you’re trying to represent. I would advice you switch over to more BARs or M1941 Johnson LMGs as the more appropriate choices.
Early war pilots in the pacific would not have been issued with any SMGs, at all, only M1911s or .38 revolvers as personal defence weapons, so I’d recomend taking the M50 Reisings off and only giving them handguns.
Normandy
Less to say here, jolly good.
I would again urge you to choose one type of SMG per squad, but here for an additional reason. Where possible, vehicle crews (tankers, drivers, pilots) were given the more compact M3 whilst the more bulky (and better liked) Thompsons were recerved for the infantry and Paratroopers. So, give M1A1s to your regular squads, but M3s to your pilots, tankers and APC/Truck drivers. Also, the suppressed M3 is really out of place on a tanker squad, when it’s really more of a OSS weapon.
I would be a bit stricted when it comes to who gets a M1 Garand and who gets a M1 Carbine. Really, only pure riflemen should be recieving them, whilst any specialist soldiers (ie, anyone with duties aside from regular riflemen, so Engineers, Flamethrower troopers, AT soldiers and Radiomen) should be given M1 Carbines. Now, of course, you might want to give an exception here and there, so you still have some Garands in your units (such as your event Radio squad, who strictly speaking should all use M1 Carbines, but giving one of them a Garand is excusable because you do still want some variaty).
You sniper squad is solid, nice that you picked out the clearly more common Springfield in the job of the main sniping rifle, the M1 Garand was bairly used in this role during WW2. I would urge you to switch the Radioman to a M1 Carbine, for reasons stated above however.
As a sidenote, I know the game (for some reason) won’t let us do it, but it would be grand if we could give M1 Carbines to our pilots, APC/Truck drivers and tankers, as that was historicly done and the intended use of the weapon as well when designed.