Dados of Meletis in Commander

[Thanatos003]

Does the mana rule of commander supersede {Daxos of Meletis}'s second ability?

[Kaylesh]

Does the mana rule of commander supersede {Daxos of Meletis}'s second ability?

Any mana source still taps for its own amount and type, Daxos just lets you use it as though it was any color.
So, basically, any spell you hit with Daxos gets its cost changed to {X}, where X is its CMC.
The colors you use don't actually change, for things that care. Cast  {Bring to Light} for 5x{U}, then the amount of colors used is 1.