Who is the RWQFSFASXC or Shadow Bonnie?
I think that this, puppet and Nightmare are the mysterious animatronics on the franchise and now we gonna talk about the most mystery shadow ever in FNAF and why we have two version of RWQFSFASXC.
We need to star from the first version in the game, the version that appears in the office in FNAF 2:

That is the first version of Shadow Bonnie and the most realistic version of it.
We can see here that the model looks like Toy Bonnie so obviously is Toy Bonnie...or not!
I think it is Spring Bonnie and i know that very people tried to compare the models of RWQFSFASXC and Spring Bonnie and even in the FNAF World they are different models but in one FNAF 4 minigame we can see a version of Spring Bonnie that looks like Shadow Bonnie:

And I know that very persons compare the teeth and they are different but if we compare the teeth in Shadow Bonnie whit Toy Bonnie we can see that they are different so why Shadow Bonnie is Toy Bonnie if Shadow Bonnie has got more teeth than Toy Bonnie?
Now we gonna remember the 2 version that we saw in FNAF 3:

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Now we have 2 version of RWQFSFASXC, we have the dark original sprite version and purple sprite version. Back to Spring Bonnie, if we compare the teeth of Springtrap(that is the only Spring Bonnie realistic version we saw in the game) and Shadow Bonnie we can see that they are different because Springtrap has got more teeth but Toy Bonnie has got any less teeth.
Now we gonna look to the purple one sprite, we see that he looks very like Springtrap but Spring Bonnie his right in is front, and just in the middle of them too, there is Fredbear so this is the Fredbear's Family Diner, the Fredbear restaurant. In this minigame we can see that RWQFSFASXC is like crashed, like the FNAF World one:

Who this Strange Guy remembers you, yes, I know, it looks absolutely like purple guy, if you cut the ears and put the yellow emblem, it looks very like Purple Guy:

So what i think is that this Shadow Bonnie purple version is just to represent the Purple Guy in the Spring Bonnie springlock suit,
So we just need to discover if they black version are or are not Spring Bonnie. We can see there two Shadow animatronic versions, the Shadow Freddy and the Shadow Bonnie so this is just what we need the know that these shadow animatronic are the Fredbear's Family Diner principal one, but Shadow Freddy is Fredbear and I will explain why, if we just compare the Spring Bonnie minigame sprite whit the dark Shadow Bonnie minigame sprite, they are not very different, they have similarities, and the purple one that represents purple guy is for the people discover that Shadow Bonnie is Spring Bonnie because you know that Purple Guy is Springtrap and he uses the Spring Bonnie suit in the  Fredbear's Family Diner so that is the reason that the purple Shadow Bonnie is Purple Guy, because he looks like Purple Guy and because he represents Spring Bonnie Shadow Suit.
And then we just need to see another thing to prove that Spring Bonnie is Shadow Bonnie.
Just look at this picture:

Now i will show you who this shadows belong: