Spoiler for :
Oh, damn, you're right. I didn't know much about Les Miserables, so I looked up this Fantine person...and it sounds exactly like Tsugumi, except in Tsugumi's case, things eventually get better for her. Come to think of it though, I've heard that Les Miserables is extremely popular in Japan, so maybe the writers were inspired by it.
Yep, Tsugumi is permanently 17 years old. Come to think of it, it makes me wonder just how long she could keep up the whole front for her and her family...I wonder what sort of cover they use after LeMU, or how they manage to survive financially (I'm inclined to think that the Kuranari family was given some sort of "compensation" by the government or with the help of You, but it's never said. Or maybe Takeshi's family has enough money that they decided to give them).
Given that they don't seem to be having any financial issues in the Drama CDs, I think they got some sum of money- Tsugumi is said to have a job, but I'm not sure if Takeshi has one or is completing his college education after LeMU. Since I don't think two people could make enough money in a few weeks to support a family of four, they must have gotten something.
On the other hand, since Remember11 is on the verge of being released, perhaps we'll find the meaning of the title- though according to some research I did, there are some sort of plot holes that are unresolved at the end of the game (though apparently the PSP version fixed it so those plotholes were cleared.) Ever17 had a few plot holes as well, so I guess maybe KID just forgot about some of their lesser plot elements.