Before I give some input here, I'd like to ask a question. How comprehensive are these Related Moves sections supposed to be? By that I mean that if a move differs from another, should every single difference between them be listed - accuracy, type, differences in effect, and power in the case of attacking moves?
As an example, on the Yawn page, it simply says that Sleep Powder is a Grass-type equivalent, whereas on the Sleep Powder page, it says that Yawn is a Normal-type equivalent, but puts the target to sleep at the end of the second turn (neglecting to mention accuracy differences).
Also, since no mention of max PP is given in any of the Related Moves sections, are we to assume that max PP is a non-issue?