In the last sentence, would it also make sense to use the conditional as in..."mais je sais que le jour viendra bientôt où j'aurais enfin le

I think the future tense (j'aurai enfin le courage) makes more sense because the sentence states "le jour viendra bientôt" which is in the future tense. I think if the first part of the sentence was more conditional (as in "a day might come when I will finally have the courage), then the conditional would work.