In amateur racing sure, maybe you could ask a manufacturer for just a "torque curve." With how competitive pro motorsport is, and how big a deal signing an engine contract is, you have got to get every bit of data you can in advance.
The cooling requirements and temperature sensitivity of an engine are not trivial points. Everyone knows about torque curves and mass... it's carefully characterizing everything else that has the potential to set a winner apart.
They would be foolish to overlook every detail. So when you say coolant and water temperatures are big factors are you suggesting that there is large difference in operating temperature and that these difference influence the design of a green field chassis project?
Thats not how it happens.
Brawn certainly had to go through that exercise when Honda pulled out because their chassis and aero concept was already in manufacture.
For newt year all teams start with a green field project. The refuelling ban means a totally new car,suspension and aero dynamic concept. Drivability becomes the key decision point in the engine selection.
Engine temp changes with different fuel load can vary so all engines will need a different cooling capacity and oil flow will need to be increased. The netchange for each engine will not be linear and will only be interesting from the point of view that it will influence the chassis design.
you still want the engine with the best performance curve characteristics.
engine oil and water temp curves are part of the secondary requires like;
what is the electrical system like
oil pump design determining oil tank location, and water plumbing determining radiator location.
The actual engine oil and water temps are managed through design to keep them within the optimal range.
I would agree that for a brown field project the oil and water temps are critical so they do not influence the layout of the car through necessitating major design changes like a new floor, side pods and front wing.
For a green fields project, the temps are a moot point and there are bigger decision points that influence which engines is bolted to the rear of the car.