TL:DR ; 'Eden' as depicted in the comic book is not real, but is a representation of a real prospect for sanctuary.
Gabriela never claims that the co-ordinates will lead the children to 'Eden', at least not in the form it is depicted in the comic book. It is only after Logan see's the co-ordinates in the comic book that he makes the assumption that this is why Gabriela is trying to get Laura there: out of some idealist mythology based on fictional propaganda intended to be “ice cream for bedwetters”. Just like Dr. Rice, who assumed the hospital support staff were "too poor and stupid" to understand what was happening, Logan has underestimated Gabriella's intelligence.
After reading the comic book, Logan believe's Gabriella brought Laura to him because she thought Eden was literally existent and The Wolverine was 'a real hero', a perceived naivety which Logan is at first angered by.
The real reason Gabriela does this, however is because her unseen and unnamed contacts who are arranging sanctuary for the children have set up a rendezvous point at the co-ordinates. This is no accident, or co-incidence; using a location in a 'comic book' is a clever cypher that would evade detection. If each child were given a comic book that contains those co-ordinates, even if they were caught in possession of it; it's just a comic book. Infact, the only reason the location is identified in the first place is because the transigen-proxy mercenary Pierce finds the co-ordinates written in plain sight, not 'hidden' in the comic book. Not only will the comic book 'hide' the location of the rendezvous, but it's likely the younger, more naive children really did believe they were heading to 'a paradise': a necessary deception to help motivate them in their journey, and allay their fears.
When they arrive at 'Eden', the older escapee Rictor explains that this was always the plan: to embed the idea in the children that they had to arrive in this destination by a certain time, in order to move safely across the border on schedule. The fact that Riktor is seen communicating via Hamm Radio to an unseen person, and confirming safe passage is enough to confirm that these contacts are very real; and the fact that Dr. Rice instructs the mercenaries that they must prioritize intercepting the mutants before they cross the border confirms that there is some kind of sanctuary for them, and it is a very real impediment to their re-capture.
Additionally, Gabriela brings Laura to Logan not because she thinks he is a knight in shining armour (as Logan assumes from reading the comics), but because:
Laura is Logan's Genetic 'Child', and her best choice of ward is someone who feels a connection or a sense of responsibility towards her (which, whilst seemingly a mistake at first given logans disposition, proves to be well founded)