No one died directly next to Balin when he fell, but his colony met their end in Moria, with Ori (who recorded their final moments in the Book of Mazarbul) and Óin (killed by the Watcher in the Water) dying shortly after him, and others like Frár, Lóni, and Náli perishing in the same final battles, all ultimately trapped by Orcs and the Balrog in the Chamber of Mazarbul.
T.A. 2994 𝑫𝒆𝒔𝒕𝒓𝒖𝒄𝒕𝒊𝒐𝒏 𝒐𝒇 𝑩𝒂𝒍𝒊𝒏'𝒔 𝒄𝒐𝒍𝒐𝒏𝒚 𝒊𝒏 𝑴𝒐𝒓𝒊𝒂. 𝑫𝒆𝒂𝒕𝒉𝒔 𝒐𝒇 𝑩𝒂𝒍𝒊𝒏, 𝑶𝒊𝒏, 𝑶𝒓𝒊, 𝑭𝒍𝒐𝒊, 𝑭𝒓𝒂𝒓, 𝑳𝒐𝒏𝒊, 𝒂𝒏𝒅 𝑵𝒂𝒍𝒊. Though the riches of Erebor made the Dwarves prosperous again, there were many who longed to return to Moria.
Ori was one of the several Dwarves that accompanied Balin to the lost Dwarf-realm within Moria in TA 2989, to begin a colony there. Though this was successful at first, the colony was overwhelmed in a long struggle with the goblins there, and was destroyed in TA 2994 when the Balrog Durin's Bane emerged.
Thror was later slain in Moria by a goblin, and Thrain II established a new home for his people in the Blue Mountains far west of the Misty Mountains and Moria. Thrain II's reign was short, however: he was captured by Sauron, tortured, and killed.
Owen Flynn plus by the Third Age, the dwarven kingdoms had largely shut their doors on the world, so news and knowledge from their realms was probably few and far between. Given that Gimli wasn't even aware his cousin Balin was dead reflects this.
In the books, Legolas actually screamed in terror when he realized that a Balrog was coming. It was the Balrogs that rounded up the elves for Morgoth, to be corrupted into orcs.
As his "rightful heir," Dáin succeeded Thorin as King under the Mountain, and King of all of Durin's folk.
Canonically, Balin is the only dwarf from the The Quest of Erebor that is mentioned as visiting Bilbo after he returns to the Shire but based on the number of mentions of dwarven visitors to him over the years I'm sure a few of the others may have come back West at some point, in addition to other dwarves who knew him ...
After the battle, the Arkenstone was placed by Bard upon Thorin's chest within his tomb deep underneath Erebor, and so was returned to the earth at last.
Why did Fili and Kili have to die? There are a few different theories as to why Tolkien had Fili and Kili die at the end of The Hobbit. One theory is that he was emphasizing the important and loyal role that Fili and Kili had as sister-sons of Thorin, an important relationship in medieval literature.
As a Maia, Gandalf was an angelic being in human form, in service to the Creator (Eru Ilúvatar) and the Creator's 'Secret Fire'. He took on the specific form of an old man as a sign of his humility. His role was to advise but never to attempt to match Sauron's strength.
But that's actually the answer: Eru Said So . The Undying Lands are a place for immortal beings (Eldar), and mortals are forbidden from entering.
But the archer was just the first of the orcs who came up the Silverlode. After a fierce battle in the halls there was a final stand in the Chamber of Mazarbul but the dwarves were completely wiped out. The Fellowship of the Ring later found Balin's tomb whilst journeying through Moria in 3019.
'The Fellowship of the Ring' (2001)
If Gandalf had stayed dead after his sacrifice in The Fellowship of the Ring, then his demise would be the saddest in the trilogy, but since he came back, the saddest single death scene of all three movies goes to Boromir's.
No. Thorins Bloodline is the line of Durin, which is survived by King Dain Ironfoot, and later his son, King Thorin Stonehelm.
It's possible that Gollum's prolonged search for the ring allowed it to maintain a significant power over him, suspending his aging process. In contrast, Bilbo's exposure to the ring's influence waned after he willingly (mostly) relinquished it, allowing his aging to resume more noticeably.
Whatever happened to the dwarves was recorded in that large tome, which can be found in the chapter “The Bridge of Khazad-dûm”. There was no communication between Balin's group and Erebor before this so there was no way Gimli, or anyone else, could have known about it.
Sauron recovered the Seven Rings from information provided by Celebrimbor, and gave them to the leaders of the seven kindreds of the Dwarves: Durin's Folk (Longbeards), Firebeards, Broadbeams, Ironfists, Stiffbeards, Blacklocks, and Stonefoots, though a tradition of Durin's Folk claimed that Durin received his ring ...
Dáin II or Dáin Ironfoot (Third Age 2767 – 3019, aged 252 years) was the Lord of the Iron Hills and King under the Mountain.
Erebor retained the vast majority of the wealth under the leadership of Dain. Presumably a great deal would have been spent rebuilding Erebor and helping the dwarves could resettle there, though we don't have exact numbers on that - certainly by the time of the Council of Elrond it had become a thriving city once more.
King Thror was beheaded, Thrain fled in despair and was never seen again, and Frerin was killed in battle. The unthinkable had occurred: without anybody realizing the significance of what had happened, the half-elf Thorin had become the de facto heir to Erebor.
Tolkien's description of Gollum conforms to a Catholic – and Thomistic – account of envy, which is a “sadness of the soul”; and it is Gollum's unbearable sadness and his unquenchable desire for the one Ring that marks his character.
But at the Council of Elrond, Gandalf very specifically says he fought all nine. He drew four of them off when he fled northward at dawn; "This helped, a little, for there were only five, not nine, when your camp was attacked."
Tolkien's Legolas is extremely introverted. He just doesn't have much to say directly to anyone, perhaps because he's thousands of years old. His odd relationship with Gimli draws him out in a way the hobbits never do, and that's mostly after Frodo and Sam leave the Fellowship.