I think Mieu continued to be a combat android, programmed to protect her master(s): Rhys's lineage. I believe she went on to kick butt when necessary and act as a bodyguard the rest of the time. Sorry, I don't project as much personality on Mieu as others do. I think she was more emotional than Wren, but that doesn't mean she felt things like longing, sentimentality or romantic love, etc.
Toyo Ozaki can draw her in all the candy cane outfits and wedding gowns she wants. I think Mieu is much more interesting as a tough killing machine with total loyalty to Rhys's family.