More along the lines with what I'm thinking right here. Maybe not literally, Idt you're being literal here either but I believe that Vegapunk is key here. That he helps infuse the DF into the sword somehow. I don't think Oda will limit just Zoans to being infused with inanimate objects, just seems unlikely tbh.No joke but i think how inanimate objects have devil fruit abilities is through the process they were made because as someone mentioned they do not have mouths.
So for instance swords having devil fruits. I reckon, when creating a sword they crush the devil fruit or something then put it into the core of the sword? Idk lol. Although i do believe Vegapunk did it in this way or in a similar manner.
Or he just ate the fruit himself and as a swordsman, he mainly uses his sword as a way of using his power.