The answer from the current Xbox listing
Game Pass catalog inclusion is not confirmed by the supplied official evidence. The current US Xbox product page lists Aliens: Fireteam Elite 2 for purchase at $49.99 and the Premium Edition at $69.99 instead of displaying an Included with Game Pass label.
That storefront state can change after publication, so the accurate conclusion is unconfirmed rather than never. If catalog access determines your purchase, check the live Xbox listing and the current Game Pass library before downloading.
Why the page still mentions Game Pass
The Xbox listing separately states that console online multiplayer requires an eligible Xbox Game Pass subscription sold apart from the game. This is the platform's online-play requirement, not evidence that the $49.99 game purchase is replaced by a catalog subscription.
For console co-op, budget for two separate items: access to the game and a subscription tier that permits online multiplayer. Players staying in single-player do not need that online feature merely to use the officially listed single-player mode.
Co-op and Play Anywhere labels
The Xbox page lists online co-op for two to four players along with Xbox cross-platform multiplayer and co-op. The same listing carries the Xbox Play Anywhere capability label, a distinct storefront capability that should not be confused with Game Pass catalog membership.
The game's official site also confirms cross-platform co-op and cross-platform voice chat more generally. A mixed-platform group should still keep all copies current, because the launch patch included a fix for cross-platform friend voice chat.
How to verify before paying
On the live Xbox product page, look for an explicit catalog badge or a subscription install option rather than assuming the phrase Game Pass in the multiplayer disclaimer means inclusion. Then confirm that your console subscription tier allows online multiplayer.
Use the displayed regional checkout price as the final number. The $49.99 Standard and $69.99 Premium figures cited here are current US store prices, and later sales, taxes or regional pricing may produce a different total.
