Behold an Unthinkable Present...
Did you know that the role between the two almost got switched earlier on? Well maybe not in a literal sense. But originally, Caulia was intended to have a bubbly, happy sunshine kind of personality while Lonnete, the closeted introvert one. I wasn't planning on making Lia the anxious wreck at first, because the premise of Bocchi the sniper war hero veteran sounds stupid... But then I decided to went with it anyway, exactly because it sounds stupid...
Anyways, this version of Lia never faced the same hardship, so she probably never got the chance to grow out of her shell. Lonnete probably enlisted as a mechanic at first and would later become a mech pilot, hence all the severe third degree burns on her. She would lose all of her cheerful persona in the war, riddled with the same trauma that plagued the original Lia- only for her, she'd probably hide it all behind a smile. In this version of the story, Lia would be too shy to confess and would probably see it as an absolutely unacceptable insubordination to even think of such a thing. While Lonnete... well, you have seen how OG Lia acts.
(The lesson here is that suffering builds character, peeps. We authors totally do it for an absolutely discernable reason >:3)