Who is the "other" with explaination from the text in Sherman Alexie's, What it means to say Phoenix, Arizona? Would it be Thomas, Victor,...

Both Victor and Thomas are perfect examples of the other.
You have a lot of evidence to argue both, but if you need to choose one I think that
there is a lot more subtle evidence in support of Victor as being the true other. Thomas
has a more obvious otherness to him, but often the hinted otherness with Victor allows
for greater analysis. Think of the airplane conversation with Cathy. Thomas initiates
the conversation while Victor would be perfectly content with his own thoughts. Through
out the story Victor separates himself from others (as in this case) which begs the
question of why? One can assume that Victor is use to being ostracized as he is the
other among his people.

Another example is Victor and the
Tribal council. Why is he not given the money needed to bring his father back home. They
claim it is due to a lack of funds, but there is more hidden between the lines there.
How is Victor different from the other Indians that we meet? He seems to struggle within
himself a bit. He can either be more like Thomas, and be more accepting of his heritage,
or he can turn his back on who he is.

I think that you will
have a lot more to write about if you choose Victor as your
other.