Short answers, pulled from the story.
The company replaced the word hobbit with halfling by 1978 after receiving a cease and desist letter from the Tolkien Estate. This legal pressure forced TSR to remove the original term from all future publications shortly after the initial release of the game in 1974.
The first Monster Manual published in 1977 described three specific subraces: hairfoot, stout, and tallfellow. These variations defined how players could customize their characters within the rules before later editions expanded these options significantly over time.
The Dark Sun setting presented wiry halflings who seldom exceeded three and a half feet in height and lived as shaman-ruled barbaric cannibals beyond the Ringing Mountains. A handful inhabited the Pristine Tower instead of the jungle settlements while wargamer Timothy Linward noted that these savage humanoid-eating tribes drew inspiration from Victorian hysteria regarding indigenous cultures.
Regis served as a notable halfling rogue within the Companions of the Hall led by Drizzt Do'Urden and carried a crystal pendant capable of charming people during his adventures. He saved the day in the final battle of The Crystal Shard released in 1988 and his actions mirrored those of Bilbo Baggins in key moments of conflict.
Yondalla stood as the chief goddess of the halfling pantheon and member of the core group in the third edition with two aspects known to followers: the Provider and the Protector. As the Provider she increased the growing rate of plants and animals to any speed she chose while her symbol featured a shield with a cornucopia motif representing protection and fertility.