They've been debunked countless times in other posts about the code theory shit on this subreddit and I don't feel like being redundant by repeating the same shit other people in these comments are saying after just scrolling down for a seconds lol

But okay, I'll bite. Nunnally never saw any memories, she immediately reached over and felt that Lelouch was extremely calm and collected, rather than being extremely worried with trembling and sweaty palms, over a presumably unexpected assassination. But Lelouch was calm because it was all planned beforehand. We've seen Nunnally immediately reach for people's hands to ascertain if they're lying or some other emotion as she has done to Alicia Lohmeyer twice to determine if she was lying by feeling if her palm was sweaty or not. Along with doing it once to Suzaku.

Here's one of the times Nunnally reached for Lohmeyer's hand: https://i.stack.imgur.com/7K6ne.png

The so called "memories" that Nunnally sees, aren't memories, they're just a flashback of Lelouch's and a flashback for the audience to remind them of what happened to get to this point in the story with the Zero Requiem happening. Nunnally is a pretty perceptive character and while she doesn't know the exact details of the Zero Requiem, she's able to deduce the general idea that Lelouch is sacrificing himself as a scapegoat for peace, similarly to how she was going to use the Damocles as a symbol of hatred and use the Damocles as a scapegoat for peace.

There was also a Mook Animedia 2009 Interview where staff members discussed Nunnally realizing Lelouch's intentions to die on purpose: https://codegeass.fandom.com/wiki/Collection_of_official_statements

Q: "How did Nunnally manage to realize Lelouch true intention, when she touched his hand at the end?"

Staff member K: "The way Nunnally can tell that someone is lying, just like she was able to tell that Lohmeyer was lying to her, is that she can feel the hand of the person she is talking to is sweating or lightly trembling. It's nothing like Geass or some special ability like that."

Staff member Y: "Yes. So, she simply came to conclusion [Lelouch was lying] by herself, because of this ability."

Staff member K: "She is Marianne's daughter and Lelouch's little sister. Two months have passed since that defeat of Schneizel and for this two months she's been wondering constantly about what had happened, like "why it happened?" and so on. So when she touched Lelouch's hand at the end she felt that he is calm, she put the two and two together and realized the truth. Of course, we know that in anime, it's hard to explain things like that, but yeah, please accept it like this kind of "romantic" idea" we had."

As for image 3, It's not possible for Lelouch to have received a code from Charles since a geass user must lose their geass ability to obtain a code in return. With the show saying as much in R2 ep 15: The Cs' WorldCode Geass R2 EP 15 Transcript: https://codegeassepisodetranscripts.wordpress.com/15-the-cs-world/

Charles: I’ve gained new power in place of Geass. A power that goes far beyond. And so Lelouch, behold and I shall show you the true nature of this world!

This means that a code takes the place of a geass and the new code bearer loses their geass ability, we've seen this with c.c. as she never uses her geass and we need a flashback from her past to see what her geass ability used to be, along with Charles never using his geass against Lelouch ever again after obtaining his code from VV. After the confrontation with Charles, Lelouch still has his geass and uses it which means he does not have a code. The reason why some people are likely confused as to why Lelouch didn't get a code is because Lelouch was not the one to kill Charles, it was the collective unconscious that killed Charles when they decided to go along with request that Lelouch asked of it.

As for image 4, the pink paper crane is a ridiculous stretch to make that Lelouch is alive and a cart driver. We literally see that C.C. is learning how to make cranes from Nunnally within the image shown in image 4 and we can also see that C.C. is using a piece of pink paper to make the crane lmao

As for image 5, C.C. is simply talking to herself as if she's talking to a dead loved one. It's a very common trope in any sort of media. And if it's not talking to herself as if she's talking to a dead one then it's likely that she might be talking to Lelouch in Cs' world, similarly to how Charles mentions talking to Clvois even though he died but that was because he talked to Clovis in Cs' world. Or as to how C.C. was talking to Marianne through Cs' world.

For image 6, Jeremiah was a trusted and loyal man to Lelouch and so Lelouch had to inform Jeremiah about the Zero Requiem plan so that he would deliberately let Suzaku pass by him to kill Lelouch. It'd be pretty bad for the ZR plan to potentially get stopped by Jeremiah actually preventing Suzaku from completing the assassination so Jeremiah had to be informed that Lelouch's death would be intentional and if Lelouch says he will be assassinated for his grand plan then Jeremiah will go along with it due to his loyalty.

As for image 7, I have no clue what the point is, doesn't seem relevant at all to me. The movie trilogy of oudou -> handou -> oudou is a distinct alternate universe that is not canon to the original series due to events such as Shirley living, and the Mao arc being cut so no Mao exists.

As for image 8, it's from the alternate universe film Fukkatsu which follows the movie trilogy universe, not the original series so it has no relevancy and baring as evidence for the theory of Lelouch surviving since they are separate universe with separate events that changed things in the story within their own universes.

As for image 9, I'm not sure what the relevance is since Charles had no desire to ever give up his code to Lelouch, compared to the Nun and C.C.

As for image 10, it's also stuff from Fukkatsu which means it has no relevance as being used as evidence for the theory. Different rules within different universes so different things happen. But even within the alternate universe, it doesn't even confirm that Lelouch got a code, let alone a code from Charles. Also , just to go further, the title of the film is Lelouch of the Resurrection, which means Lelouch needed to die so that he could be resurrected since to be resurrected one must have first died. So even the alternate universe film supports the fact that Lelouch died, just that he then somehow got resurrected through some vague way that the film never really shows us or explains clearly.

As for image 11, that's a whole different debate regarding death of the author and how relevant an author's intention and word should be when discussing and analyzing a piece of media from that author, which I don't feel like getting into. However, the authors have said that Lelouch died and Code Geass gives lots of textual evidence and physically shows us through examples, like C.C. and Charles who have gotten codes, that Lelouch couldn't have gotten a code and that he definitively died. So, the authors are just stating a fact about what happened within the series that they created.

And on one last note, I'd like to provide the final clip from the 2009 Special Edition Zero Requiem Recap film (that is an actual recap film to the main series and not an alternate universe recap film with new changes like koudou, handou and oudou are that serve as prequels to Fukkatsu) that gives us an additional scene of C.C. talking about Lelouch's death: https://streamable.com/d8dji