We have no idea where Killer is, or what he's doing, let alone whether he's heard about the wedding, and even less that he has any idea how Luffy will react to it! He doesn't know where Luffy is or what he's doing, why would he assume he was sneaking into the wedding? There are too many logical jumps there.
I think every supernova know Luffy a bit, because he's the brat who punched a tenryūbito and you know, every supernova could have just died there because of him.
He also did Enies Lobby for a friend (Robin), also Impel Down and Marineford for a friend/brother (Ace) but I don't know for sure if the newspapers talked about Ace/Luffy.
Either way, he knows he punched a tenryunito for a friend and did Ennies Lobby for a friend ( well, we actually don't know if the newspapers talked about the relation with Robin).
Either way, he has seen what happened at Sabaody, he knows what he would do for a friend and so long…
but yeah, I'm not certain or anything about Killer going at this wedding, but very positive that there will be a Luffy/Law/Kidd alliance.
But why Luffy? Why not literally anyone else? I get that people want to see the Kid/Law/Luffy ally fight again, but that doesn't mean that it would make sense.
Because he knows that his target is Kaidou. http://www.mangareader.net/one-piece/793/10
Umm what? You think their alliance could have killed Shanks? Get real, if they were stomped by Kaido, they would have lost to Shanks too.
I was kind of ironic to the plot-twist Oda is ( probably ) doing.
Oda (chapter 793): Good, their target isn't the same, so no one can say the Luffy/Law/Kidd alliance is VERY convenient with a sarcastic tone.
Oda (chapter795): Okay, so Kaidou just fell from a sky-island –-that could have been anywhere but right above Kidd's island---- just right on Kidd's very little island ( we'll assume this is his island ). They're facing Kaidou, and I will somehow manage to do Law/Kidd/Luffy again.
There's only two options; they got locked up or were left for dead (must likely).
You know, they also could have escaped…
Maybe Hawkins looked at his cards and just thought "ok i'm fucked, not even gonna fight. just get the fuck outta here...."
And Oda had no reason not to show us Killer and Hawkins locked up ( and all their crewmates ). Plus, a supernova would never die offscreen. So, they definitely escaped (or maybe Hawkins joined Kaidou's crew but don't think he did imo. )