An excerpt:
In addition to Data, [Brent] Spiner has had four other roles in the franchise: Lore, Data’s evil twin, introduced in “Datalore” and deactivated in the “Descent” two-parter; B-4, Data and Lore’s prototype, introduced in Nemesis, and also seen disassembled in “Remembrance”; Noonian Soong, Data’s creator, in “Brothers” (alongside Lore), and seen again as a dream image and a holographic recording in “Birthright Part 1” and “Inheritance,” respectively; and Arik Soong, Noonian’s ancestor, in the Enterprise three-parter “Borderland”/”Cold Station 12″/”The Augments.”
This episode adds a fifth, and it’s in keeping with the others: Altan Inigo Soong, the son of Noonian. (Though it’s not mentioned, his mother is presumably Noonian’s wife Juliana O’Donnell, established in “Inheritance.” I’m also just assuming his middle name is a tribute to the swordsman from The Princess Bride, and if it isn’t, I don’t care, because in my head it is, so there, nyah nyah.)