Patching colour palettes optimally

[lightwo]

There are virtually zero games that have alternate colour palettes for Game Boy Player, so applying alternate colours/filters is obviously necessary.

Best I could find in regards to patching ROMs are existing "colour restoration" ROM hacks, but this is obviously not ideal as not every game got the attention of a hack developer. Is there any other, possibly automated approach that would work on original hardware?

And as an aside, in regards to Game Boy Interface, does applying LUTs or filters introduce any lag? Anything close to a frame of input lag is hard to tolerate, considering it's possible to configure GBI to have very low latency otherwise.