While I hate the idea that some really sweet, old cards will essentially be lost to the sands of time if this is a popular solution, this might be unavoidable in our current environment, at least in some cases
Of course, cube size is entirely at the discretion of the cube designer
Songs can be played by paying their ink cost, or they can be played for free if you exert a character of a specific cost (or higher) to sing the card
The bad news is, you have to pay at least 7 mana for it to give +1/+1 to other birds, and this Azorius commander gets worse with commander tax, so Id add it to the 99 of a deck filled with birds instead
The spell won't be countered when the ability resolves, but its controller will still manifest dread
But the payoff is worth it for it to generate one mana of any color