Miguel is Leena’s biological father, although Una has similar hair color to Miguel… It is possible he fathered Una before he left with Wazuki but I’m not sure if Una’s age was ever referenced anywhere. He does look young, but he seems to be older than Mel in the sense he talks mature. Also, he may be a few years younger and just hasn’t hit a growth spurt yet
as far as both of them in Home or Another, they may be adopted by the old lady (Leena’s grandmother?) opposite the docks where Leena babysits the children swimming.
Not to change the subject, but aside from her and/or Una being adopted, Leena doesn’t get a lot of love… she is a top-notch character in terms of stats, but I’ve always felt she got the short-end of the stick both story and relationship-wise
after Serge was teleported to Another World, she just states he shouldn’t play magic tricks on her after the deep conversation and marriage she alluded to him on Opassa Beach. It’s like all that serious talk went out the window. Kid comes into play and Serge just seems to forget about his childhood friend (and future spouse) altogether. I feel like there should be a case for Leena here… I kinda wish you had the option to choose who you wanted to be with at the end, or Leena would just challenge Kid to an Arni-style tribal fist fight or something lol (that would make amazing fan art haha)