United States ArmyGeneral.Brigadier general.Colonel.Lieutenant colonel.Major.Junior captain.Captain.First lieutenant.
Despite not being married, Gaara does have a child through adoption named Shinki. Much like Gaara, Shinki boasts the Magnet Release Kekkei Genkai and is an extremely formidable sand shinobi wielding Iron Sand.
Yes he does have a child named Shinki. He has a kekkei genkai and is able to use magnetic release.
No, he doesn't get it back. But he retains all his jutsu and abilities, mainly because it is revealed that it wasn't Shukaku who protected Gaara, but his mother's will infused in the sand. However, after the Tailed Beasts are freed, Shukaku and Gaara become friends by the power of talking no jutsu and flashbacks.