Mashiro is doomed i think
Time dilation at worst she has 2 kids already Her cousin is like 5 years and Mashiro was a baby when they were separeted, when they reunite Mashiro is 15 and her cousin is 10-12 is mentioned she is younger than her making this a time dilation of 15 to 7 years. Win...
I honestly dont think Mashiro can be saved, her only posibilities seem really dim too
Time dilation as this didnt happen
Grape but saved by Zane later on
Fantasy or false memory by Nemuro (so maybe somebody else has Mashiro)
Alternate timeline
Now Time dilation at worst she has 2 kids already...