Either way SJ3 won't be back on SMALLVILLE.
I also don't see KK coming back or Rosey. At this point they just need a focus on wrapping up the Darkseid plot, Lex clone plot and end the series properly. I don't see them adding any more ghost from the past...obviously Lionel, Martha & Jonathan will be in eps the next 11...but bringing in more obscure characters from the past is a waste at this point...we do have new characters coming up Blue Beetle & Booster Gold...hopefully that will be it.