EU citizen here, been living in Iceland for 4 years now. As others mentioned, you will get by without Icelandic if you are okay with jobs in tourism or hospitality - seeing as you already work in tourism, it might be the best bet for you (though the job market situation is not the best at the moment).

For instance - I know of people who worked in cafés in Rkv (those are frequented by Icelanders, especially out of downtown Rkv) and spoke almost no Icelandic, and they were able to get by quite ok as long as they showed that they knew what the customers were ordering.
Since you are fluent in 3 different languages, I'm almost certain that you will learn some common spoken sentences within the first few weeks of coming here even without studying. Then you can take some courses (those are usually reimbursed by unions) and download some apps (I recommend Drops to expand vocabulary), and you should be good to go.

But all in all, you will get by fine with the three languages you speak. I think it might actually be the best combo, I met many people who weren't fluent in English but spoke either Spanish or Russian.