For those who may be interested, below is the proposed timeline for Hundir and Helmir - subject to unforseen events
Some events are "actual" events in the Silmarillion with events of Hundir's life added.
It is odd in how things have turned out. I had decided that there would be an entanglement with Sauron's werewolves at some stage. Later, in a game, on a random item roll a sword that was crafted as a wolfs-bane was found. Now poor Hundir, thanks to his connection with the Silmarils is subject to fate, just like the elves. I suspect this will be something large and hairy.
Time Line for Hundir and Helmir
455 Morgoth breaks the Siege of Angband, Dagor Bragollach ("Battle of Sudden Flame"). Deaths of Fingolfin, Angrod, Aegnor, Hador, Gundor, and Bregolas, Fingon becomes High King of the Noldor, Gil-galad sent to the Falas
Hundir (22) and Helmir (26) return to Rivil’s Well
They meet Khadran
456 Death of Fingolfin in single combat with Morgoth.
Death of Gundor.
Emeldir, wife of Barahir, leads their people out of Dorthonion to Brethil.
Hundir and Helmir first contact with Orodreth at Minas Tirith
457 Sauron captures Minas Tirith, Húrin and Huor depart Gondolin. Barahir and his outlaws in Dorthonion, Orcs defeated in the Forest of Brethil.
Hundir and Helmir leave Minas Tirith just before Sauron attacks – are pursued by wargs and werewolves.
458 Húrin and Huor enter Gondolin.
459 Húrin and Huor leave Gondolin.
460 Deaths of Barahir, Belegund, Baragund, and all the outlaws save Beren Erchamion.
The attack against Barahir’s band temporarily relieves pressure on Hundir and Helmir
462 Death of Galdor. Orcs invade Beleriand.
The last of the Eldar leave Dorthonion.
Decision made to move east to be closer to the lands of the sons of Fëanor.
First contact with Easterlings.
463 Easterlings swear false loyalty to Maedhros.
464 Birth of Túrin. Beren leaves Dorthonion and meets Lúthien in the forest of Doriath.
465 Birth of Brandir. Quest for the Silmaril. Death of Finrod.
Sauron flees to Dorthonion/Taur- nu-Fuin which now becomes more dangerous, filled with fell spirits and vampires.
Around this time the decision is made to flee Dorthonion.
466 Birth of Lalaith. Silmaril taken from Morgoth; Beren loses his hand to Carcharoth; the Hunting of the Wolf; first death of Beren Erchamion.
467 First death of Lúthien. Lúthien sings Beren back from Mandos.
468 Birth of Hunthor, Thingol refuses to join the Union of Maedhros.
469 Death of Lalaith. Orcs driven from Beleriand. Beren and Lúthien return to Middle-earth.
470 Births of Dior and Hardang.
471 Death of Halmir, Huor weds Rían.
472 Nirnaeth Arnoediad ("Battle of Unnumbered Tears"), Year of Lamentation. Birth of Tuor. Deaths of Fingon, Huor, Glóredhel, Azaghâl, Haldir, Hundar and Rían. Turgon becomes High King of the Noldor.
At this time, if they survive, Hundir will be 39, Helmir 43
473 Birth of Nienor, Túrin sent to Doriath. Fall of the Falas, Brithombar and Eglarest ruined, Gil-galad and Cirdan flee to Balar. Havens of Sirion constructed.
481 Túrin and Beleg in Doriath.