Modified code in the Android Open Source Project gerrit associates changes relating to the Qualcomm Snapdragon 835 to target devices codenamed “Walleye,” “Muskie,” and “Taimen,” all three apparently being operative names of the next generation Google Pixel devices. The changes were picked up by WinFuture.
Some user debug changes relating to the MSM8998, the part name Qualcomm assigns to the Snapdragon 835, are also being applied to the Sailfish and Marlin models — the current Pixel and Pixel XL phones.
Walleye and Muskie seem to refer to phones while Taimen is said to be a larger form factor phone. How these all come together to become all the Google Pixel 2 devices will parse down to the specifications — we think all that will come in due time.