Мафия Alternative. Zombieland.

Secondly, if we have circumstantial evidence, then the ankh itself is an Egyptian cross.

The ankh, firstly... Secondly, it's on the level of Crossfire Vista)))

Ankh-Morpork refers to Pratchett's Discworld, where there is a book called "Guards! Guards!"

Yes, and this collection of works also includes a whole bunch of books on various themes, from magic and Christmas to the mysteries of the afterlife. Moreover, if we take a specific book, the Night Watch themselves cannot be called ideal warriors. Half of them are cowards, and most are not above using dirty tricks in fights. You've found some flimsy evidence. But you pulled me out of my slumber, thanks:)
There are still arguments to be made, otherwise so much has been written here...

The bison is giving off negative vibes from day one.

What a weirdo :D

And now let's look at Neira herself :D
Evidence number 1 - "The Code of the Perfect Warrior"
Let's look at the picture in the caption:) I'm not an anime fan, I don't know the essence of this cartoon, but why aren't these two ladies warriors?) They are definitely no worse than the Night Watch from Ankh-Morpork))) Not to mention that Japan is the homeland of samurai, warriors who possess a code. Let's move on:)
Evidence number 2 - "a footprint with a strange cross"
It's inquisitorial footwear:) And inquisitors are often mentioned in the song from your profile;) I don't know which of these is circumstantial and which is real, but both are quite plausible.

So Neira is a very good candidate for execution:)

As for the evidence as a whole, the warrior's code fits well with Morninga, the text in the signature.

Here are two supporters of my execution.

I'll look for something else about the evidence now:)
But the evidence against Neira is good, in my opinion:)