-Syngas
Syngas is a mixture of hydrogen, carbon monoxide, and carbon dioxide. It can be used to make ammonia, synthetic oil, and fuel. Syngas is made by reacting fossil fuels or plant matter with high-temperature steam in the presence of a catalyst. This would allow you to be flexible with your raw material sources. For example, if you didn't feel like switching your farms to make canola for more lubricant, you could gassify some coal into syngas and convert that to synthetic lubricant with the Fischer-Tropsch process. Similarly, if you want a renewable source of ammonia, you could gassify some wood, separate out the hydrogen, and react that with nitrogen in the Haber-Bosch process.
-Hydraulics
I would like to see the fluid transportation aspect to be more fleshed out. Pipes could be used to distribute hydraulic work, with pressure and flow rate being the parameters (akin to torque and angular velocity), governed by a simplified version of the Bernoulli equation. Pressure could drop over distance, depending on the roughness of the pipe wall. The maximum flow rate would be determined by the pipe diameter and the maximum pressure would be determined by the pipe material composition and thickness.
This would enable an easier division of power between machines without needing shaft busses or complex shaft splitting, but at the cost of lower efficiency due to pressure drops. Additionally, this could allow for more modular fluid transport. For example, if one needed only a small quantity of water at low pressure, a small pump and thin-walled pipes of small diameter might suffice. However, if one needed a large amount of water (say for a fusion reactor), a much larger pump (perhaps an upgradable multiblock) and thick-walled large-diameter pipes could be used.
Similarly, steam could be used as an energy transportation method with the same parameters as above, if we assume saturated steam (otherwise with superheated steam, temperature would be an additional parameter). In many industrial plants, a natural gas fired boiler is used to supply steam to the entire facility to drive components and supply process heat. The same could be applied to Rotarycraft, with a complex steam network supplying a workshop of variously sized of steam-driven turbines. These turbine would be much smaller than the massive ones in Reactorcraft.