Is Gara from the Uzumaki clan?
No, it doesn't mean Gaara is of Uzumaki Clan because: If Gaara was of Uzumaki Clan, it would play a big part in the story and Kishimoto would've definitely use it somehow, but neither of Gaara's parents are implied to be from that clan.
Who is Gaara wife?
Hakuto
Gaara meets the woman the Suna Council has found as his partner for the marriage meeting:
Hakuto of the Hōki family. His first impression of her is that she is beautiful, something that embarrasses him once he realises that she could possible become his wife.
What clan is Gaara in?
Kazekage Clan
Gaara/Clan