star wars - What do Han and Luke know about Rey's abandonment?

In The Force Awakens, Rey is waiting for her family, that she doesn't seem to remember. She has Force flashbacks that give some hints when she touched Luke's lightsaber. The novelization for those flashbacks shows that her family member left her in a wooded area and said to wait and that he/she would come back for her (see this answer).

What is the situation when she is left, as far as we know from canon? Who left her on Jakku? What, if anything, do the main characters Luke, Han, etc, know about her? Why was she left on Jakku when the novelization shows her separation from family happened in a forested area? (I don't have the novelization so I'm hoping there is more in it than there is in the movie. I also have my fingers crossed for a good extended-edition of The Force Awakens.)

From watching the movie, it seemed pretty clear to me that she was not left on Jakku by said family member.

I may be reading too much into expressions, but I think it's appropriate given that J.J. Abrams and company intended to speak more with actions than words, as opposed to the prequel trilogy. Here are some things I noticed from the movie:

• Rey, as a child seen in flashback, is held back by Unkar Plutt^{1 2 3} while she screams "come back" at the departing spaceship.


• At the end of The Force Awakens, it seems as if Luke was surprised to see her. Maybe he thought she was dead?


• Throughout the movie, Han seems to feel remorse or guilt toward Rey. The most telling scene in my memory is Han and Rey piloting the Falcon to Maz Kanata's place. Rey essentially says she didn't believe there would be so much green in all of the galaxy. Han's face shows grief and guilt.

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^{I'm kind of trying to validate my theory that Rey is Luke's daughter and that he may have thought she was dead (killed at the same time the mother was killed?), and that Han knew what happened to her or was responsible for it—that she grew up alone and hungry in the desert—when no one could find Luke. But, I'll be just as happy to be proved wrong with some quotes from the novel. Or maybe this.}

¹ See this screen clip that was posted to imgur and reddit and since been removed.

² Another site that shows the image of Young Rey and Unkar.

³ I watched the movie twice and looked and listened closely during this part as it was one of the questions I wanted answered. Unkar's face is also partially visible, but the only photos I've found didn't capture it the way a 3D widescreen theater shows it.