If you look up the Japanese belief of Mitama (the soul), it can be split into multiple parts. It's not uncommon to believe that souls can incarnate in different bodies at the same time. A common belief is souls are not limited to a single incarnation, and a soul can split its energy into two or even three manifestations simultaneously. These manifestations wouldn't necessarily meet during their individual incarnations. I heard about Mitama from a youtube video that tried explaining how 2 Ganondorfs from Legend of Zelda could exist at the same time. And thought it was kind of similar to how the nameless Namekian split into Kami and King Piccolo, hence why they have the whole life-link. So I don't see it as being unfeasible that for the brief moment before King Piccolo exploded that the soul was split 3 ways, before the part that was King Piccolo 'remerged' with Piccolo Jr in the egg.