Very evil indeed. Although I believe that the paradox won't foil Tempus, because even though this might make Clark allergic to Lois (in a sense) it really doesn't stop them from getting together. (as many Kryptonite laced handcuff jokes might imply).
"But, Mom, I love Lois! And when I'm with her I'm just like everyone else. How can that not be fate?"
At first, I thought Tempus was going to kidnap Lois and deliver her to the Kents of Smallville, Kansas as a younger sister for their newly acquired son. If Tempus, could travel through time and space, who says he couldn't steal the space cradle from B39's warehouse in 1993 and "crash land it" outside the Kent's farmhouse in 1967? But I'm afraid that's the plot of someone else's evil story.
I digress. As always loving the Tempus story. I enjoy his sort of evilness more than all the other villains combined. I think it's the irony.
This is a great set-up and I'd surely enjoy seeing where it led.