Two days ago, Lineage OS released its first build of OREO based rom for selected devices. Although Oneplus 2 is not in the initial list, two xda developers have developed two separated unofficial version hoping to be listed as the official by lineage team.
New version of AOSiP and Lineage OS were updated and can be downloaded from here. AOSiP and Lineage OS released by Shreesha and Lineage os by ozzy were updated and they all were tested and considered as stable. (lineage by ozzy needs a bit more improvement).