I am really struggling with the Portuguese pronunciation here. I think it might be that Spanish and English are so different from this in some cases. So with my combined knowledge of those two languages, it makes learning another language's pronunciation even harder! I would really appreciate anyone's help here.
One tip I saw on another discussion that is helping me out: the Portuguese r sounds like our h (roughly) whenever it would be rolled if it were Spanish (when doubled, or at the beginning of words).
Also, just keep practicing. It's very common to start out speaking your third language with the accent of your second language! :-D But eventually your brain gets trained enough to realize there are more than two languages.
Once you hit that point, it becomes much easier! But it can take a long time (and lots of practice/repetition) to get there.
Also be aware that some colors don't change, like verde and azul. Usually if they don't end in -o or -a they don't change, but if they do then they need to match the noun (one exception I am aware of: rosa is always rosa).
But they may still need to agree with the number. For example, even though azul is azul for both masculine and feminine nouns, it becomes azuis if the noun is plural.