[ A little something I stumbled upon that pretty much summarizes up almost everything I think regarding Nicki’s demise — and to which I added commentary on. You can find my thoughts in italics. ]
Reasons why the character Nicki from The Vampire Lestat might actually be alive… original source: here.
1. Nicki had two violins. One from his home village and one Lestat bought him. He sent one to Lestat when he went into the fire. Where is the other? — I believe Nicki kept his original Violin and sent back the gifted one because, at the time, he hated Lestat. Further, it is highly doubtful Armand would have purchased him another one. Not that it would have been hard for him to acquire another violin, if he so wanted. But, why go through the hassle if he already had one sitting there?
2. How do we know Armand didn’t have Eleni lie in the letter to try to lure him back to Paris? Or that Armand wrote the note himself and pretended to be Eleni? He, did, after all- lie to Louis saying Lestat was dead and lied to Lestat saying Louis was dead. — Besides, he’s also known for his painting. He must have known how to forge Eleni’s handwriting with very little effort, especially being a vampire and all.
3. Lestat placed a gold cross around Nicki’s neck while they were under Les Innocents. It’s never described that Nicki took this cross off. It would not have burned to ash with him. Where is his cross — and why was it never sent to Lestat along with his other things? And speaking of ash,.. wouldn’t it have been nice to send Lestat an urn with Nicki’s ashes? Or, at least some of them?!
4. The mysterious musician friend described in Interview with the vampire who wrote ‘too disturbing’ music that would ‘never sell’ according to Louis. It’s implied that Lestat made this unnamed friend a vampire and he died in the town house fire when Louis threw the lamp at Lestat. Is it possible this musician was a vampire all along and Louis couldn’t tell? Yes, we see him described with fang marks on his throat at one point but that could be a wound that would take a few minutes to heal. (Blood play with Lestat maybe?) Lestat claimed he would make the musician a vampire and supposedly did; but what if he was one all along? With Louis’ lack of experience would he have noticed? Could Nicki have secretly had an unexplained cameo in Interview with the vampire?
No, then Lestat would know he’s alive, wouldn’t he? And he’d have said something in The Vampire Lestat? Unless he’s keeping one secret from us for some reason. Something Anne meant to cover later? But why does Lestat credit himself as having made only Louis, Claudia, Gabrielle, and Nicki vampires by The Vampire Lestat? Why does he not mention this musician friend in New Orleans when telling his own story? Could he have re-met Nicki there and never elaborated for some reason? — Or, perhaps there is a turn in the storyline we aren’t aware of yet. Maybe Nicki is no longer recognizable by Lestat? Who knows, though… it’s funny that Lestat never could find Nicki in Heaven or Hell. I have always thought that very suspicious. Also.. There are quite a few references to Religious themes tied with Nicki. Perhaps there is something to be said for it…
5. Isn’t Lestat the slightest bit suspicious of the fact that everyone who witnessed Nicki’s demise is either dead by the time he goes back to Paris or they are …Armand – who is known for lying to Lestat that Louis is dead and telling Louis that Lestat was dead. — Further.. what ever became of Eleni? Do we never hear from her again? Did she die with everyone else, or had she left with Nicolas somewhere else?
6. Armand does not like Gabrielle, makes up excuses to dislike her, once planted the vision in Lestat’s head to kill both Gabrielle and Nicki and even destroyed Claudia to get Louis to himself. He lied to Louis about Lestat being dead, and lied to Lestat about Louis being dead. — What if, what if, even though Armand does not like Nicki and placed that vision in Lestat’s head, that LATER ON realized he could possibly use Nicki as a bargaining chip some way? I mean.. Lestat never liked Armand. Doing the favor of babysitting was one point for him. What if “bringing him back” is his ultimate goal so Lestat would eventually “love” him and possibly further push Louis away from Lestat, so that again he could have Louis all for himself?!
7. Nicki hated Lestat when Lestat left. Is it at all possible he faked his own death, wrote the note or had the note written so Lestat would not try to track him down? — I also feel like Nicki, feeling abandoned all over again, wanted to possibly hurt Lestat emotionally. Even though he was the one that pushed him away, and either faked his death for everyone, or plotted to fake it with the others so only Lestat would think him dead.
8. Nicolas, in the musical Lestat, is presumed dead. Lestat finds out he’s dead. Then at the end in the reprise of From the dead the lyrics only confirm that Claudia is dead. Nicki’s fate is left vague and uncertain..
[In conclusion, I feel like there was a very big plot that was hidden from Lestat for whatever reason. Nicolas was alive, or if he had died, came back in some way — and then that was hidden from Lestat. I also feel whoever devised or was a part of this plan to keep Nicki from Lestat relied heavily on Lestat’s nature and ability to dismiss things and try to forget. We never hear much of Nicki from Lestat, because it is a painful part of his past — and Lestat does not like to show his feelings like that. He would rather not dwell on it. Further…. would Lestat really admit to being wrong if he ever found out Nicki was alive? Just curious on that… He might just keep that a secret himself, especially if everyone else thought him to be dead as well. JUST A THOUGHT. Anyway,… I hope Nicki gets mentioned in the new book.]
THIS. I have always been annoyed about the disappearance of that “musician friend” from IWTV… this explanation intrigues me.
I-want-my-IWTV 
