Would Croation people get offended if I did this while I was over there?

Honestly... a couple of those lines sound a bit predatory no matter where they're employed. Flirting and chatting are fine, but "you're extremely attractive" is not polite, nor is "you're fit", because it sounds like you're judging them on something they can't alter. That is the aspect of this you should change to something more charming. Flirting, winking, laughing, and acting interested in their ideas and words are perfectly gracious, but blurting out what you think of them physically is not elegant at all.