Nonono Yuri couldn't use her legs anymore when she used all that remained of her power at the end of the story, she stop aging physically when she first got her power at 12 years old I think what Homura E.N.D meant was that it was said that she couldn't grow anymore at the end of the manga.
—— proof goes here: https://dynasty-scans.com/chapters/gamma_ch20#36
And Marina actually saw Yuri 4 years before they actually met and Marina had had short hair at the time so I think they know each other by now.