The books do a great job at including well-reasoned exceptions to most of the racial prejudice and conflict.
First off, my take on goblins is that they don't really dislike anyone. Disorderly, selfish and uncaring of others, perhaps - but not strictly disliking. This makes it easy for the goblin PCs to not be forced into picking fights all the time. For example, even though the halflings seem to dislike and be ashamed of the goblins, the goblins still (begrudgingly) protect them. So perhaps goblins aren't as ill-mannered and mean-spirited as one could be led to believe?
For the wolfkin, it says some individuals dislike the tribal forest life and look for hire as guards and trackers. Perhaps trying to live out a more """human""" life? Perhaps this wolf seeks to become more civilized and has a strong dislike for his ferocious and barbaric kin? Obviously, the more rural folk will be prejudiced against him, but with three goblins, a big wolf and a dwarf - they might prefer to keep their distance instead of picking a fight.
Now when it comes to the dwarf... I read FbL dwarves as being above all pragmatic. The dwarf might look down upon the rest of his party, or he might like them, or be completely neutral. Either way there is something that he wants done, so one could assume he will do his best to make the group work. Perhaps the dwarf will be the face of the party ( ) when interacting with people skeptical of them and simply wave their worries away in a sort of "Yeah, yeah, you don't like goblins and wolves. Neither do I. But here we are, so what can you do about it, eh?" kind of way.
Have you thought about how the group will initially come together?