Question: is gaara part of the uzumaki clan?
Answer: Gaara of the Sand just so happens to be the only (major) character who is not Uzumaki and has their distinctive hair color. He was also a jinchiriki, he possessed the One Tails Shukaku. I can't say for certain that he is definitely Uzumaki; Kankuro and Temari do not have the fire red hair of Uzumaki Clan members.