Forgive the double post, but I'm going to try to put this all in one understandable chain.
More or less, but here's a more detailed breakdown of events (from my Granite 2 153 save, my memory, and some poking into legends):
1. Smallhands was under siege for most of the year in my turn (152, "The Scalded Attack") until early winter.
2. Migrants (including the dwarves that would become Nogood and Laterigrade) arrived. I, noticing that the siege had ended, decided to open the bridge.
3. The undead echidna we now know as Roastedscaled, which had been lurking around for my entire turn and slipped my mind, attacked the slower migrants. I sent out the militia to deal with it.
4. The militia is having a hard time dealing with it, with militiadwarves Del and Olon dying of blood loss (Del was blinded and in pain for a while, so his death was a mercy). The rest of the militiadwarves along with the miners I conscripted ended up being hospitalized. The migrants that failed to reach the fortress before Roastedscaled did (including Nogood) bled to death from their injuries.
5. Roastedscaled ran into the entrance, blocking any hauling of corpses (also preventing the injured in the hospital from getting water).
6. Granite 1, 153 hits (I didn't realize it was Granite until Granite 2 came), what followed were events that happened so fast I had to go to legends to get clarification:
7. The human necromancer Vusdom Tunnelyore tries to attack the fortress with a few human ghouls (153, "The Assault of Cuts"). He revives four dwarf corpses as forlorn ghouls (this world's name for intelligent undead), which I realize are still counted as citizens.
8. He also revives a large amount of animal corpses on the surface before running off, which leads to a large amount of undead animals right next to the open entrance. This does not end well.
9. Granite 2 arrives on the calender. Goden Dedukoshur, who is the forlorn ghoul who was renamed "Nogood", decides to take a nap after fighting an undead animal or two. The only dwarves who are not in an area compromised by undead animals are Salmeuk (taking a nap) and Zan "Laterigrade" Monomduthal (just slightly away from the drawbridge lever...). And the rest, as they say, is history.
Edit: Nogood came back perfectly fine after razing Cactushexes before suddenly turning into a ghost. Anyways, I’ll go finish my turn (I apologize for the delay).
10. Goden "Nogood" Dedukoshur spends years as a militia dwarf in Smallhands, training with Moldath until both are Legendary Fighters. They each take a squad of new recruits.
11. In 158, Nogood's spirit arises as a ghost in Smallhands.
12. Nogood's spirit is put to rest, while the forlorn ghoul, Nogood, is sent on a mission.
13. Nogood, the forlorn ghoul returns from the mission miraculously cured of his undead condition.
14. Nogood is now a normal, very strong and tough, dwarf.
Is that right?
It's close, but not quite. The actual series of events are more confusing:
10. As you said, Goden "Nogood" Dedukoshur takes over the Gravewardens and Moldath takes over the Rainbow Raptors. Both are legendary.
11. Nogood doesn't have a ghost appear for the time from his resurrection up until the Razing of Cactushexes. I think intelligent undead block the rising of their ghosts, but not necessarily whatever activates the rising (IIRC, the undead Olon (who was locked in fighting until nogood's turn) didn't have a ghost rise until after being killed, when the others who died in the battle at the end of 152 had ghosts rise earlier)
12. Nogood is sent out in several raids. Most notably, the razing of Cactushexes, where he turns into a ghost upon or shortly after coming back. Perhaps the thing that causes ghosts to rise doesn't take into account whether they are alive but off the map. While I initially thought that the ghost of Nogood was separate from Nogood (the forlorn ghoul militia commander), Nogood (the forum user) pointed out that it appears the ghost replaced his undead body. If I had to guess, since the ghost body is technically the body of the dwarf that the ghost is, Nogood (the forlorn ghoul militia commander) became Nogood (the ghost forlorn ghoul militia commander) without actually dying.
13. As Nogood (the ghost forlorn ghoul) technically never died, he was still part of the militia despite being a ghost. This meant I could still send him on missions. So I engraved a slab for Nogood, and then sent Nogood (the ghost forlorn ghoul militia commander) on a simple raid to the kobold fortress. Then, I placed the slab, putting Nogood (the ghost forlorn ghoul militia commander) "to rest" while he was off the map and on the mission.
14. The GraveWardens return, and so has Nogood. Not exactly sure how, but if I had to guess, since Nogood (the ghost forlorn ghoul militia commander) technically did not die while on the mission, the game decided to revert Nogood (the ghost forlorn ghoul militia commander) to being Nogood (the living dwarf).
15. Nogood (the dwarf), being still the same dwarf as Nogood (the forlorn ghoul militia commander who became Nogood (the ghost forlorn ghoul militia commander)), retains all of his skills and traits from before being Nogood (the ghost forlorn ghoul militia commander). Nogood (the dwarf) is reassigned back to being the leader and militia commander of the GraveWardens.
Don't worry, it's as simple as it appears to be.