I noticed that the order in which order you get the hidden skills is the same regardless of which stone/wolf/skeleton knight you use.
In other words, if you would have missed the first one (the ending blow) you would have been taught the ending blow on the second stone. With that being said;
Stone #1: Just before the Forest temple.
Stone #2: Just before the zone where you warp into Death Mountain (where there's a bunch of geysers and archers).
Stone #3: It's near the lonely house down below Zora's domain.
Stone #4: Inside the lost woods lost woods.
Stone #5: ?
Stone #6: ?
Stone #7: ?
Like I said, the skill you get is independant of the stone you get to. You get the skills in that particular order;
Skill #1: Ending Blow
Skill #2: Shield Bash
Skill #3: Back Slice
Skill #4: Head Crack
Skill #5: ?
Skill #6: ?
Skill #7: ?
So yeah, hope that helps...everybody feel free to post the rest (haven'T got to 'em yet), maybe that can be of some help for someone.
Zx