I actually had no issue with your ending where you did; it reminded me very much of the story "The Lady and the Tiger," and I thought it a unique and ingenious solution.
I could make a case for either survivor. Your Lana isn't cannon, and she isn't perfect, but nobody is, and if she lives I won't be upset. If Lana survives they live happily ever after and your story is over but VERY well done.
On the other hand, if Lois survives you've opened up a whole new world with LOTS of room to explore some very interesting relationship possibilities. Clark grieving, Lois knowing who he is, and how each of these things impact how they work together. Will Lois be able to support Clark emotionally? Will Clark be able to accept that support? Has she been so difficult towards him up to this point *because* she's been attracted to him but fighting her attraction? (After all, he was MARRIED.) All sorts of intriguing possibilities to explore.
I look forward to seeing where you take us.
