The Wonder Twins, or a version of them, ALREADY appeared on SMALLVILLE, during the period Clark didn't have his powers. (They were meteor freaks who held the Kents hostage while Clark was sent to get something from Luthorcorp to boost their powers.)
They had different powers than the original versions, were both guys...and were ugly.
I wonder if these new ones will have pointed ears? (Quinto eat your heart out.)
Those were not the Wonder Twins. They were Kryptonite freaks who were offhandedly called the "wonder twins" by their ringleader. Other than them being related (brothers in this case), there was no connection to the wonder twins.
Even if this was the case, we met Kara in season 3, only to meet the real Kara later.
Well, it is not like Smallville has ever been preoccupied with its internal continuity.
Haha...true. Although, Smallville seems to have been decent considering it's been on for 8+ years. The only real big, big issue was the whole Veritas mess that somehow retcon and connect all the side B-plots that occured over the course of the series together.