in touching spirit bear, who were the only people cole could trust?

That is correct. Edwin and Garvey are the only two people who want Cole to have a second and even third chance. Cole's parents had repeatedly let him down and Cole really did not have any friends. Cole is angry and alone. Edwin and Garvey show Cole some tough love but, in the end, they make all the difference in Cole's transformation.

Both are incorrect. In the book it CLEARLY states he trusted anyone or anything afraid of him.

What a character states is not always what they mean. Cole is a round character with many conflicts. His inner motivations can be interpreted. Part of his emotional defence is to trust nobody. If you dig a little, Cole puts more trust in these two guys than he ever has with anyone else. The question also specifies "could" trust which includes the reader's opinion as well.

The question is very vague, it needs to state at what time in the book

At the bgining of the book Cole trusted and had faith in nobody, he used the fear of others to instatute fake trust toward himself. After the Spirit Bear attack Cole begins to trust Garvey and Edwin, because theyve always tried to help him and see what they have learned through there very own island experiences. The trust goes even deeper when Garvey and Edwin take him back to the island a second time. Toward the end Cole trusts his mom, and when Petere comes to the island Cole begins to trust him as well. Trust is something Cole had newly learned and has never encountered before Spirit Bear.