>>14807825Pretty much everyone agrees that Silver is Giovanni's kid. There's some dialog from FRLG that mentions Giovanni having a kid with long red hair.
And in the Celebi event, he's the only kid with long red hair you see talking to Giovanni. Anyone can put two and two together.
Ariana being the mother wouldn't be impossible, but it's unlikely.
You could say that maybe she and Giovanni were fuckbuddies for a time and she got pregnant and never really gave a shit about Silver which is why they have no problems battling each other.