Wave height measurements and drift hindcasting
As far as I know, the remote sensing for determining wave heights works indirectly. SAR (Synthetic Aperture Radar) and scatterometry (a form of SAR) can estimate surface winds. From a history of surface winds, you can get some idea of wave height, but I don't know how accurate. Also, SAR and scatterometers operate from low earth orbit, so a given patch of ocean is only visited from time to time.
It is also unlikely that the drift of the flaperon can be hindcasted with any degree of accuracy. The ocean currents are complex and poorly sampled, and thus chaos is likely to dominate hindcasting over any significant amount of time - as it does other complex hydrodynamic systems. The flaperon would also have been subject to influence from wind, and in a complex manner - it would vary over time with the relative wind angle, which is impossible to predict.
This sort of inherent inaccuracy is most obvious in weather models, which try a similar process - except they are forecasting. Weather models are pretty much useless more than 10 days out, and often fail spectacularly over a much shorter period.