I have noticed that as well. My fish aren't scared of me but when new people are around they hide or even go into "I'm invisible" mode (that really freaks ME out, ie. when they go all white or camoflage colour).
My clownfish, however, hide at the sight of me pretty badly, and they are among the longest that I've had fish, so I don't think it's a case of "they'll get used to people eventually." They actually were more personable before I had anemones, giving them an anemone was the worst thing ever in terms of having cute little fish that I could look at. Now I have an anemone I can look at and occasionally catch a glimpse of a fish going "Holey crap he's still out there!" and darting out of view completely.
Actually, I guess they have gotten a -little- better, when they were in a big tank I never saw them and they didn't even come out for food and they were wasting away. Now that they are in a small tank with no tankmakes their sense of security has gotten so that they at least come out for food, although they dart away right away. But, at least they're eating.
As for a mandarin and flame hawk - I did have the flame hawk when I had the mandarin. I did not notice any interaction between the two. I think they are fine tankmakes in that regard.