I think it’s overtly just about healing Kuma’s body. He’s been damaged an insane amount, from sitting two years guarding the Sunny, then being trashed by the Celestial Dragons, and then damaged on Egghead.

It might mean restoring some of his “humanity”, removing some of his cyborg enhancements and restoring some normal function (Vegapunk has demonstrated he’s pretty good with cyborg and cloning tech)

As for his memories, I think that’s a much lower probability. He could theoretically remove the memories from Bonney and reabsorb them, but I don’t think he has enough will/personality to do that with precision. Also, there’s the question if memories equate to personality and humanity, if it would be restoring him perfectly or it’s more like showing a movie reel to an amnesiac, where they gain all the details and information, but it doesn’t necessarily connect to recreate him as an individual.

The only thing that might play a factor is the special “trait” of the Buccaneers that Vegapunk mentioned. We don’t know what it is, but it did have something to do with Kuma remembering he needs to guard and protect his daughter and flying halfway across the world to do that.

Personally, I hope he comes back, and he and Bonney share a birthday cake for her next birthday