Are all three from the same dealer? With the similar
toning on all three, it would raise flags, but would not make it certain that they are
fakes.
The Arab-Sasanian coin weighs 5.4 grams? If so, it is a
fake! Arab-Sasanian coins rarely weigh over 4 grams, with most around 3.8 grams.
As for the other two, I also believe their
weights are off, but would have to send more time checking my references.