I have been asked to comment on this thread from a hair forum. I don't belong to any forums so it is always interesting when people highlight these questions to me. I am more than happy to answer any questions from research I have highlighted, so feel free to email or comment should you want more of an explanation.
Does coconut oil contain protein?
As I've said before, if it does, it is very little. I have not found any site that lists protein anywhere, as part of the content of coconut oil. It does depend on the purity of the oil that you buy. One nutrition site does list the composition as nothing and a second site lists only oils in the composition and therefore 0g - protein.
I think we need to distinguish trace amounts and significant amounts. Trace amounts means there is one grain of salt in a glass of water - will you taste it? Significant means there is a teaspoon of salt in the glass of water - now you can taste it!
Is coconut oil protein retentive?
I must correct this information. The paper cited in that discussion (I have discussed it here) says that coconut oil when used as a prewash conditioner helps to retain protein (meaning the cuticle is not likely to break off). It is not about adding protein to hair, but actually just preventing damage to the hair and therefore less protein (i.e pieces of hair/cuticle) is lost.
I am not certain why this would be a bad thing or am I missing something?
Can oils moisturise hair?
This depends on your definition of moisturise. If your regard it in the strict sense of amount of water content, then no oil is for you as oil films do slow water uptake. If you regard it as a substance that can penetrate the cortex of hair and contribute to pliability (meaning hair can move without feeling stiff) and manageability then coconut oil is for you.
I would encourage all to read ingredients to look out for in your hair conditioner .