Deadpool became Deadpool through a series of complex and sometimes convoluted events in the comics. He was originally a mercenary named Wade Wilson, who underwent experimental treatments that gave him his unique powers and personality.
There is a loose link. The version of Deadpool in Wolverine Origins provided a starting point, but the standalone Deadpool movies developed his character and story in a more distinct and expanded way, deviating from the initial portrayal to create a more focused and engaging narrative.
It's a bit of a mixed bag. While there's a link, the portrayal of Deadpool in Wolverine Origins doesn't fully align with his later, more developed storyline. Some elements were changed or not fully explored.
Obviously, the main characters are the two Deadpools. They are both versions of the same character but with potentially different backstories and personalities in this graphic novel.
In a more extreme scenario, Deadpool could end up in Arkham Asylum and think it's a new kind of S.H.I.E.L.D. facility. He'd start interacting with the inmates there, and Batman would have to step in to deal with the chaos Deadpool is causing. Deadpool would see Batman as this dark and brooding figure and keep trying to get him to lighten up.
Cable would be a great character to pair with Deadpool. Their dynamic in the comics is really interesting, with Cable being the more serious and brooding type compared to Deadpool's zaniness. In a game fanfiction, they could be on a mission together and Deadpool could be constantly annoying Cable with his jokes and antics.