I took a look at the other graphs as well and some are OK and some are not. It's obvious that either they have no idea what they are doing or know exactly what they are doing as they are selling the good with the bad. I would just pass. The odds of finding a Zoe and Sam dual signed item is pretty low but if you do it will be pricey.

I can tell you for sure that Sam's signature looks nothing like that in person.

Sam: The "W" is way off.. but the signature for "Sam" is spot on
Zoe: The clear error is the "Z", the heart, and the "S." Most Zoe's "S" I've seen are crisp

By getting them in person.

wow i would have been trick. how do you know it's not real?

Nope. Another ebay fake.