Where are their first appearances in Marvel continuity then?
The title says nothing about a first in continuity appearance, it claims to be their actual first appearances. Issue 1 is Coulson's first in continuity appearance but not his first appearance in a comic book. Nick Fury Jr. appeared at the end of Issue 7 of the Fear Itself series.
It's not up to the seller to explain the story of the book and he history of Marvel in their title on eBay. A buyer needs to educate themselves.
Also, if you're going to get that technical, issue #1 is the first appearance of Coulson as "Cheese". He is not reveled as Coulson until issue #5 or #6, again, depending how technical you want to get.
Nick Fury Jr. is not reveled as such until later issues as well (perceived issue #6). He is Staff Sargent Marcus Johnson until that point.
Either way, the market (and respective wikia's) have dictated this and we all know what is correct does not drive sales, it's perception.