I do not think Wat is something we need to build right away, it is not a wonder that helps us in an immediate way, especially if we can't hire the Priests.I'd like to focus the discussion on KC's point about X-Ville. Is it better to build Wat and observatory there or units? Wat doesn't do much good if X-ville doesn't have the surplus food to hire preists (and it wont if Marbleville is using the fish). The observatory would bring in about 20 beakers per turn after it's built and maybe an average of 25 over the rest of the game. On the other hand, building units in X-ville soon will help us take Joao's cities faster.
The Observatory is a little more difficult to assess. It will require 4-turns to complete (if my calcs are correct?) We have Divine Right, Nationalism, Gunpowder and Military Tradition to self-research. Liberalism could be next and how fast we need to research that depends upon where the other civs are in thier research? At our current research rate, it looks to be about 20 more turns of research, plus a turn or two for civic changes and no research turns to get Gold for upgrades of a Galley or two. Will the observatory pay for itself in research benefit over that time? How long can it be delayed and still be of use? If the delay makes it less attractive, then units exclusively?
After Colossus, there will be a 35 hammer overflow and units can be built at 36 Hammers per turn. With the overflow, we should be able to build two maces in three turns. After that, it is a Mace every two turns.
Horseville will produce two maces every seven turns but has the capacity with Worker turns to bump that up to a Mace every three turns.
Not sure how many Cats we'll need, 4 or 5?

Santarem, Braga, Guimaraes and Lagos are all on hills.
In answer to your question, it seems that building units in X-ville is preferable to wonders atm.
