Lubricity seems to be an issue when it comes to accuracy. It is possible for a lube to be too slick. This lubricity effect has been discussed by Dutch Schoultz in his muzzleloading accuracy system. It seems, in my estimation, that when it is too slick, the ball starts to move before the powder has had a chance to get to burning completely and it keeps moving too easily for the breach to build up pressure. The end result is a lower MV due to a lower breach pressure. This seems to be why saliva works so well as a patch lube, it is just not as slick as an oil so the ball is less prone to premature movement and the breach pressure builds more consistently resulting in a more consistent MV and this translates into more accuracy. So, I don't know how slick coconut oil is but if it is not too slick, it should work okay.
I have done an experiment with lubricants of differing lubricities to determine how they effect MV. The lubricant with the greater lubricity resulted in a lower MV indicating a lower breach pressure.