Enrichments in WvW
Doubtful, as WXP is not the same as XP. And, as only L80 characters can use Enrichments, it would not work for leveling.
Yes, they work. No, the experience enrichment doesn’t work because you do not gain — as Inculpatus says — XP in WvW, you gain WXP (or World XP) instead.
Things like the karma enrichment, though, they work fine.