This post is poorly organized. A complete recap of the overall zombie killer argument should come first. Only after that, if at all, should the Gettier cases be introduced.

The essay by Nigel Thomas is quite good, by the way. The following snippet captures a key point, and sheds much light on your discussion:

Thus zombiphiles normally (and plausibly) insist that we know of our own consciousness directly, non-inferentially. Even so, there must be some sort of cognitive process that takes me from the fact of my consciousness to my (true) belief that I am conscious. As my zombie twin is cognitively indiscernible from me, an indiscernible process, functioning in just the same way, must lead it from the fact of its non-consciousness to the equivalent mistaken belief. Given either consciousness or non-consciousness (and the same contextual circumstances: ex hypothesis, ceteris is entirely paribus) the process leads one to believe that one is conscious. It is like a stuck fuel gauge, that reads FULL whether or not there is any gas in the tank.

I recommend you edit your post and insert this quotation near the top.