Even if these people don't have iron, in the real world, a pacific northwest tribe jndependently developed advanced STEEL metallurgy from merely a few examples of knives they had traded for a few decades earlier. This is like skipping straight from the late stone age to (miniature) British Empire steel foundries in a single generation with no guidance. They went extinct a few years later, but the point is any meagre hint = tech advancement. Merely giving them a few knick knacks would make them a superpower, and he's probably going to give them fridges and generators, too. Even the journal bearing is a lot.
Qelix: A hydroelectric turbine can reach efficiencies unattainable by the friction losses in a gearbox. However, there are ofc easier ways than building a waterwheel, pouring it down a turbine and returning the flow to the main stream.... and the waterwheel itself is basically another source of losses anyway. (Other styles of turbine will only reach about 40% efficiency at best iirc, but advanced tuebines from dams are practically 100% efficient iirc. The MC's is inefficient anyway.)