Will the blessings of Allah and His angels upon the teacher of good continue as long as people act upon what they have been taught, or is it limited to the duration of the teaching only, and will these blessings be placed in the teacher's scale of good deeds on the Day of Resurrection?

The phrase "ليصلون" (they pray for blessings) is a present tense verb that denotes renewal and continuity. Allah's prayer for the seeker of knowledge signifies His mercy, while the prayers of the angels and all other creatures signify their supplication and seeking forgiveness for him. This continues until the Day of Judgment, and the reward of the seeker of knowledge does not cease with his death.