What is the dalvik speed patch?
There's absolutely no magic here caused by a mysterious "Dalvik Speed Patch". The Author said that in the comments himself by stating:

Lol... I just mention dalvik speed patch, actually it's a kanged lib file...


So it's just a wording issue that you took as a rumour.

The higher Antutu benchmark scores are very propably caused by overcklocking using the Franco Kernel only.

Regarding your second thought about the FB hack:
The FB hack has has nothing to do with this question. By the way, it's super ugly and something Facebook should be ashamed of: http://jaxenter.com/facebook-s-completely-insane-dalvik-hack-46376.html