I think we now know the identity of the hand from the Most recent Decurity Breach trailer. Take a look at this:

https://twitter.com/Popgoes6/status/1435320795358797825?s=20

Now,take a look at the hand from the Security Breach trailer:

As you can tell,they look similar. Both are damaged,both look similar to the Nightmare Animatronics,both have similar colors....here's the fun part.
Mr Glitch boy most likely is the hand. You see,he is the only Animatronic/person so far without a clear concrete identity. Therefore,this teaser is giving us a hint as to who the hand is,the Animatronic seen in the picture. Therefore,we can decide that,based off the facts we know so far,this Animatronic is most likely the Afton Amalgamation/another version of William. What this means for security breach,I don't know. But,this might be a huge clue.