The effect of the 3rd promotion of the Hermetics depends on the civ's Great People generation ability. So basically, any civ that focus on the Great People generation is a good suit for Hermetics - for science, there are Scotland and Sweden; for culture, there are Russia, Kongo, and Brazil.
Ley lines usually show up in desert, tundra, and even snow tiles. This is a result of world generation rules, as resources are considered as a compensation of features and tile yields, and will only generate after the generation of features, so biomes with least features/yields - desert, tundra, and snow - will have a lot of oil, aluminum, and uranium, so as the ley lines. Therefore, civs that can survive in extreme climates - Russia, Canada, Nubia - are feasible suits for Hermetics as well; Russia is particularly good. Nubia can also benefit from their district building bonuses.
(Australia is not the case here, as they already have a great way of receiving good adjacency bonuses, an extra +1 is kind of lackluster to them.)
For other civs, I would say that naval civs and trade based civs are more fit for the Owls. Great Admirals and Great Merchants will provide ley lines will good yields, but the Gilded Vault will benefit these civs the most - it can provide a lot of culture output, to the point which you don't really need any Theater Square - and kicks in one era/promotion earlier than the Hermetic 3rd promotion.