Luffy will most probably go through a drastic mental change after his whole crew is killed. He will not remain the same. Any sane person would not remain the same if his/her friends that are like family are murdered.
tftc,you really surprised me, a question about law are you going to kill him or are you going to recruit him? About MC's weapons you can give Dante's arsenal (google translate)
Thanks for the chapter! Looks like this is going to be the end of the Straw Hat Pirates. I think this is going to break Luffy's will and spirit like what happened shortly after Ace died at the hands of Akainu. I'm looking forward to Robin's future appearance she got after the timeskip!