Good day Guardian! I took a gander at your profile, and it shows that you already own the Arcadia Class Jump-ship (Collections > Equipment > Ships > Season 8). As for the Generalist Shell, it appears that during the New Light missions, Guardians are tasked with defeating a unique Fallen Walker in the Cosmodrome that is exclusive to the progression of the New Light questline. Apparently, defeating that Fallen Walker has a chance to drop the Generalist Shell, the Arcadia Class Jump-ship and a white rarity Khovostov. (https://www.reddit.com/r/DestinyTheGame/comments/1bmg3a3/generalist_shell/) I cannot confirm whether or not this is true, as I have the items you are seeking, but I do hope this helps!