The Frith nickel being referred to was a 1941 nickel (non-silver) planchet struck with a 1942 obverse and a 1941 Large S reverse.
I do see a faint S looking symbol in the first pic, but I suspect it is like the others above said, "seeing what you want to see vs. what is actually there" as the size of the faint S seems larger than the actual Large S would be. Also, based on the wear of the rest of the coin, it shouldn't be that faint if it was truly there.
I don't see anything in the second pic.
The last two nickels definitely do not match, as they do not have a 1941 reverse.