I don't have any trouble applying V3's head morphs to the Aeon kids. They work. They just don't look that great.

This is Mary, the Aeon adolescent girl. The Arwen morph looks okay, but not really very child-like. The second image is the HdJapanese2 morph at full strength. Interesting, but it looks more like a grandmother than a child. The last image is the HdJapanese2 morph at half-strength. Better, but still not very child-like. There are very middle-aged looking bags under the eyes.

I also end up with odd bumps in the cheeks with many head morphs, even applied at very low strengths.

I think this is just the natural result of heavily morphing a figure. DarkWhisper's Teresa character is the same. Looks great "out of the box," but the face doesn't morph well.