@Urouge -I doubt that would work.How would you command sword to become fire? But I guess constant paramecia would work.Stretching stick or something.The idea of zoan fusion is a weapon with mind of it's own.More usefull that way.But effect of life can be most likely obtained through zoans,who have something like animal spirit in them.You should ask Vegapunk.
Yeah, I'll run right over and ask him. Anyway, it'd be a bit strange surely but not impossible. I don't see why a paramecia couldn't also have a mind of its own if zoans can. Your stretching stick example is a good start. I'd imagine that if a staff ate some kind of growth paramecia, it'd wind up being like Goku's weapon from Dragonball that obeys the user.
Even if the object didn't acquire any sort of mind, there are still other ways it could work. Take Kuma's paw fruit for example, which has the power to repel anything. Infuse a shield with that power and it becomes the world's most amazing shield, even if it is mindless. Certainly that wont happen, specifically, since the paw fruit is already owned by Kuma, but it should serve as an easily understandable example of how such a concept could work.
There are certainly fruits out there that would be difficult to imagine how they would work (like Blueno's door fruit). But, in those cases, Oda simply wouldn't ever have them infused into an object to begin with so it wouldn't be an issue.