You cannot combine Dragon Stance's dragon tail attacks and the claw attacks granted by the Dragon Claws spell. They are separate unarmed attack types, and you can only use one or the other for any given attack.
You can use Ki Strike with either of the attacks, since this modifies an existing unarmed attack type.
If you were to combine Ki Strike with Dragon Stance's dragon tail, your attack (or attacks, if you used the Flurry of Blows option) would deal 1d10 + Strength modifier bludgeoning damage and 1d6 variable  type damage.
If you were to combine Ki Strike with claws from the Dragon Claws spell, your attack or attacks would deal 1d4 + Strength modifier slashing, plus 1d6 of a type depending on your dragon bloodline, plus another 1d6 variable  from Ki Strike.
 Force, negative, positive, lawful (only if you're lawful) or electricity, cold, fire or bludgeoning (if you have the Elemental Fist feat).