All three of those are very powerful symbols.The buffalo itself means power,but can also represent that you have powerful enemies.The coyote has always represented the trickster.You never know whether he means to teach you something,or try and take from you.His purpose is to confuse,and yet he is an important teacher,and we learn much from him,like how to be on guard,and trust our own instincts,instead of relying on what we're told.

Wolf,however,is a true friend.He symbolizes family,and loyalty.He will never let you down,or turn his back on you,and would die protecting you.

As for the dream,itself,the buffalo letting you pet it may have been a way for it to show you that you have some power in your own life(to have been able to approach,and touch such a large animal,took knowing it would not,or could not harm you,in other words,possession of your own power)

Coyote was not friendly.From a Native American point of view,this would be seen as a sign that he was angered because he knew he could not trick you,that you would see through his wily ways.It could also be that he was trying to tell you that someone you think is trying to be a friend,is really not,and to be on guard.

That the dream finished with wolf coming around, shows that family means a lot to you,as it should,and that your loyalty to family and friends will carry you through, no matter what you ever have to face.