Is there an equivalent to elemental mages (p. 17, MITS) for wujen?
Yes. The elemental oppositions in wuxing are a bit different: Fire opposes Metal Metal opposes Wood Wood opposes Earth Earth opposes Water Water opposes Fire So a wujen aligned with Fire (for example) gets a bonus with combat spells and fire spirits but suffers a penalty for manipulation spells and ancestor spirits or spirits of man (associated with Metal).