Here we go again...
Family connections are always powerful. Especially when someone's relationship with one member of the family is complex and fraught, bringing other family members into the story can lead to some very interesting interactions.
If a PC in your game has a background that includes a significant family member, it can be tempting to introduce that person at some point. But instead, how about introducing a different family member? At first there's no mention of the significant one, but then slowly a story emerges...
[Reminder: Our guest commentators have not seen Rogue One. Part of the fun is seeing how their untainted impressions re-interpret the movie through the lens of our comic.]
Ahh yes, the backstory. And not just any backstory, your mother. Potentially, one of the most important aspects of your backstory. Harry Potter and the Natural 20 shows just how powerful this one aspect of your backstory can be.
Or, you know, this could be nothing more than a standard family album, a homemade DVD compilation of clips, and nothing more important than that.
On the other hand, "if you ever get lost you can use it to find us". PLOT HOOK!
In Jim's defense, having a mother and having a relevant mother are two totally different things. If you're out adventuring and your mom is just at home doing chores and taking care of the farm or whatever, you basically never have to really think about her.
A good GM though, can take any mother and make them a relevant mother. If your PCs think their mother was perfectly normal, give her a sketchy or exciting past. If they think she's just safe at home, get her kidnapped. These things help them explore/develop their backstory by making them think about their childhood.
GM: It looks like a memory crystal.
Bria: Cool! I plug it in.
GM: You see a collection of folders containing genealogical presentations.
Bria: Oh. Blechh.
GM: Family slide shows, that sort of stuff. There's one about your grandmother before she married. Another one full of pet photos.
GM: Your mind goes back and you remember your mother giving you this crystal when you were eight years old.
Lyra: Keep this safe, Jyn. If you ever get lost you can use it to find us.
Bria: I have a mother?
Cassian: Isn't that in your background?
Chirrut: Does it need to be?