There's possibly a correlation between the two, though I'm unsure of how legitimate it is. Were I to put myself in their shoes, I think they dress this way not because it looks good, but because they either happen to like the colors (no matter how poorly they go together), or they do so in order to satisfy some age-related fetish. As I've seen certain pieces of fiction and other media that show children as being incapable of dressing themselves adequately (e.g., dressing in colors that don't match, dressing in fabrics that clash, &c.). Considering Kevin and his ilk have gotten their ideas on women from the media they consume, it stands to reason Ripley may have done the same, and thus dresses like this in order to appear younger. All to satisfy his sexual proclivities.