Oda wouldn't want to have Luffy "bite the hand that fed him" so I'd presume he wouldn't go after Shanks directly. My guess is that he falls to whoever becomes the final villain among the Yonko or Marines
Shanks falls sometime during this whole yonko arc, either Akainu or blackbeard. They're pretty much the only two people I see as being able to defeat shanks. Blackbeard seemed to want to fight him but just not at the parmount war.
If Big Mom are Kaido are to be considered hyped, I'd say the hype right before he interacts in the story as a fighter will be even more. Not counting his Marineford feats for now.
Luuffee and Uussoppu most likely still gotta meet his crew before they get defeated
Honestly I think Shanks lives. No need to kill him and nobody is strong enough if he's with his crew. I think he'll watch as Luffy surpasses him and finds One Piece/fights whoever.