Think he will go his own way for a while, he dont want to be PK, just to discover more about the Will of D. so think he will go after poneglyphs until the Final War.
For Laftel, think its impossible that anyone besides the crew will get there, to me the Laftel arc will be the like Skypea, a adventure only with the SH.
And of course Law will come back at the Final War, he is a D. and have the fruit that is a counter to Imu immortality, think its clear at this point that he is set to give his life to indo the Immortality Surgery on Imu and let him be defeated by Luffy. To me the Luffy and Law vs Doffy is kind a proto version of Luffy and Law vs Imu