In all honesty, had she called them friends aloud, Link would not have been entirely comfortable with the term. But it wouldn't have been Navi's fault. Perhaps they were friends, now. He was a bad judge of those kinds of things. Very few of his friends spoke rather than Mooed.
"Er, looking forward to it, I suppose?" he phrased it as a question and scratched the back of his neck. "So, need any help unloading all that stuff you brought over?"