What are some similiarities and differences between control, lube, and seal oil systems?

I assume you are talking about turbine/generator oil systems. All three systems may use the same oil and be part of the same system or they may all be different systems and use different oils. Control oil is normally used as a hydraulic fluid and will usually be at a higher pressure. Lube oil will be used for lubrication of bearings and pressure will be much less than the control oil system. Seal oil is used to maintain a seal around the rotating shaft of the generator so the hydrogen used for cooling doesn't escape. The pressure of the seal oil will vary with the pressure of hydrogen in the generator. Usually ~5 psi greater than H2 pressure.