Superboy - nope
Lex - Nope
These two have long futures and history.
Lois
I’m guessing Clark’s mother. Then its off to his hide-away for maturing, growth and come back as chris reeves.
The four actors mentioned are Clark, Lex, Lana, and Chloe.
Clark and Lex can’t be killed off because of their future positions within the Superman franchise.
Lana and Chloe: The story would progress just fine without either one of them. If Chloe is killed off, that could push Lois into the journalism career that is her future in the franchise. If Lana is killed off, that would be one more thing to push an already amoral and evil Lex further into criminality and megalomania.