I have been following but not commenting as of late. Is someone suggesting you need 2 colorless mana to actually cast new kozilek through omni? If so that is incorrct. You definitely don't need colorless mana to cast through omni. As for the repeal suggestion if you want to bounce anything with over 0 cmc you need to have mana to do so. Repealing a candel will result in 1U having to be paid. You cannot use omni to repeal a candel.