Question, isn't there any possibility that there is an official translation in Spanish?
There was, but the translator stopped updating it, so it eventually got archived. See the ESP.7z of the
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. Same thing happened to the French translation.
In their current state, trying to use them with the latest version will only result in a very broken game.
At present, the best bet is to use the MTL tool to auto-translate to either.
And no, the MTL tool cannot update old translations. A proper Translation Editor for the text system would need to be created for that (or the slow process of manually adding the missing text blocks; a process that needs to be thorough and checked over in depth to prevent translation-related bugs such as broken dialogue choices that result in softlocks)