Keith, with his Duty alignment, will be respectful to Arpegius. He might ask if all ghosts are naked or if it's just Arpegius' preference, but the question comes out of pure curiosity and with absolutely no judgment.

He will accept Protection, so long as he can transfer it at will to whoever might need it more than him. If he can't, the Knowledge to find out that FoB is alive/that the label is lying about their death, at the very least, he will consider that all the thanks he needs.

(If forced to choose re: protection, he will insist that the Spirit Summon and protection go to Ivan and Pao-lin; it doesn't matter which so long as they each have one.)

HE WILL BID ARP FAREWELL WITH A "THANKS, AND THANKS AGAIN," OBTAINING INTENSE FLASHBACKS OF HIS CATCHPHRASE ;-;