Huh...that's really weird. My guess would be that only Volbeat would inherit those egg moves from a parent. So, if, say a Male Machop with Seismic Toss bred with an Illumise, the Volbeat babies would have Seismic Toss, and the Illumise babies would not.
Since it doesn't work for an Illumise to have those 4 egg moves, I'd be fine with just Encore and Baton Pass. (I can breed on the others myself if someone requests a Volbeat). I'd give you 2 shinies for it, since it wouldn't have 4 egg moves :)
Ok, well just let me know whenever you decide :) I know I have both of those in stock. Also, just something I noticed, I think the banner in your sig is too big, the bottom is cut off. I had a similar problem with mine, you just have to resize it to make it smaller.
Hey, great :) I was actually planning on getting that one myself, since its Hidden Ability is only available through Hidden Grotto (which is a huge pain). Would you still be up for it?