I've made the history and sources of WT beliefs and doctrines a bit of a hobby for the past two years.
Russell and Barbour are direct "descendants" of Miller and the resulting Second Advent movement. Doctrines borrowed or refashioned from Adventist theology include : Biblical chronology based dating to predict the Second coming of Christ, "soul sleep " (the dead being conscience of nothing), a "remnant" of Christ's annointed followers rising during the final days and proclaiming the Second Advent, the "remnant" being raised to heaven before Jesus cleanses the earth of wickedness, after the "cleansing" all the dead would be resurrected and taught by the "remnant", those resurrected ones that are redeemed will live forever on a paradise earth, Jesus uses one channel of communication (the "remnant") to communicate with the world before the Advent, the "remnant" receive special understanding of bible prophecy by holy spirit, and more...