I'd say it might be one of those:
- Luffy
He could be stupid enough to eat it, and he might survive since we still don't know why Blackbeard was able to have two DF.
If it's because he's a D, that would mean that Luffy can too, since he's also a D.
- Sanji
He's a cook, his element is clearly fire, and he's been falling behind in the Monster Trio, so he's a good candidate.
My only points against it is that he's the best swimmer, and his "dream" is to find All Blue...
- Momo
I'll be honest, I'm not sure why, but I think that Momo might do it.
Being a kid, he could be stupid like Luffy was when he was a kid, and he could try to eat that DF.
He would then become a "Fire Dragon", or something like that...
He might be able to survive thanks to the fact that the "Dragon DF" he has was manufactured, and wasn't a real one... who knows...