My US infantry Omaha beach+how to make GasMask bag?

If Im not mistaken, although I very well maybe be, the black bags were not life vests. Altough, both items were issued to US soldiers on the D-day landings, along with arm bands treated with chemicals that would change colors in the presence of deadly or poisonous gasses.  The black bag was a waterproof plastic bag for gasmasks, and the vest was a flotation device, among other uses, however both were ditched by many of the soldiers, the vest for its weight, and the bag just because it was one more thing to hang on to.  Please correct me if I am wrong.

To answer your questions

1. To make the Gas Mask bag. You can use one of two methods. Either use Two Part Epoxy Putty (Milliput or Duro) and sculpt your own. Or use a surplus small square kitbag. You can leave some off of figures as these were an item that was quickly ditched.

2. To make your rifle slings and helmet straps. Tin Foil tends to be too thin (In my opinion) it does not hold its shape well. I use foil from wine bottle tops, or pudding containers. If you search through the previous posts with the search section you will find several good posts on exactly how to do these.

3. As far as your figures. If you are building this as large as described, you're putting in a lot of effort, but you painted over previously painted figures without stripping them. If you were to strip the paint off first then add your primer and re-paint, you will not only end up with the correct colour but better looking figures and a well executed diorama.

Just a suggestion.

Cheers;

Gregory