My Feral Wolverine Theories
We already know the comics won't be strictly followed because Tyler Dayspring/Genesis hasn't been introduced. There will definitely be some type of "workaround" in how Logan goes feral and then completely gets his Adamantium back.
Here are a few theories on how we might get "Feral" Logan...
Morph turns into Wolverine and is doing the classic "come here" pose during a fight with someone. This is before he, Logan, Deathstrike, and Sabretooth get to the room that has all the "laser discs". This is also why there is a "metal" sound when the claws come out. Something fails during the Adamantium feed and Logan goes into his feral state.
That is indeed Logan doing his classic pose, after he gets his Adamantium back. His body then somehow rejects the Adamantium due to an error in the process. We hear a monstrous roar and then we see him change into his feral state.
We get Feral Wolverine right off the bat at the start of the season without a failed re-bonding of Adamantium. The trauma that Magneto put him through was enough to turn him feral. At the end of the trailer, we see Logan, along with Sabretooth, Deathstrike, and Morph. When we actually see the episode, Wolverine will be in his "feral" uniform and the Adamantium bonding is just about to begin... But then Apocalypse appears with Gambit as Death. He orders Gambit to kill Morph and Deathstrike and then has Sabretooth reveal himself as being on his side. He then has Sabretooth show off his own Adamantium claws. Wolverine and Sabretooth then battle. Wolverine defeats Sabretooth. Apocalypse strips the Adamantium from Sabretooth, bonds it to Wolverine's skeleton, and then we have Wolverine as "War". He then does his classic pose.
Also, in the trailer, we see Wolverine in his classic costume in the big group shot where Cyclops, Jean, and Beast are in their X-Corp uniforms. I'm thinking that's a Red Herring and when that particular episode comes out, they will change it to his "feral" uniform and it will be before the Deathstrike/Sabretooth scene.