Well, all of the languages you've listed are romance languages, stemming from Latin. English, while technically a Germanic language, has had a lot of influence from French and Latin (and most of French came from Latin), so there are a lot of cognates between these languages and English. Furthermore, all of these languages belong to the Indo-European language family, so there will be similar grammar and structure - not the same by any means, but similar. And they also all use the Roman alphabet like English. So, yes, it will definitely be easier to learn one of these languages if you know English as opposed to knowing some completely unrelated language. I personally (as a native English speaker) have even noticed that learning French has helped me understand things of English because of the amount of borrowing English has done from French, so it goes both ways. A lot of the words of Latin root in English are scientific or legal terms, so learning any of these languages should help you somewhat to understand denser English texts as well.

That's right, all they come from Latín, also portugues and a few more lenguages.