Help with Character Names for Writing

I need help with naming some Characters in a writing or story that I am working on. I have that main character name and I have the parents names. I need help with four older sisters and a twin sister names. I also need help with another name for the main character, because she has been kidnapped the criminals who have done this call her a different name. I need help with the female kidnapper. I need ideas for first and middle names. I am also trying not to use mainstream names. But I will take any kind of suggestion and run with it.
Here is what I have got so far:
[name_u]Rory[/name_u] [name_f]Eleanor[/name_f] [name_m]Garrett[/name_m] (main)
[name_f]Anna[/name_f] [name_f]Christine[/name_f] [name_m]Garrett[/name_m] (Mother)
[name_m]Timothy[/name_m] [name_u]Michael[/name_u] [name_m]Garrett[/name_m] (Father)
[name_m]Joseph[/name_m] [name_u]Dean[/name_u] [name_m]Stewart[/name_m] (Kidnapper)

[name_u]Rory[/name_u]'s Twin: [name_f]Lucy[/name_f] [name_f]Abigail[/name_f]
[name_u]Rory[/name_u]'s Alternate Name: [name_f]Francesca[/name_f] [name_f]Marie[/name_f] “Chessa”
[name_f]Sister[/name_f] 1: [name_f]Georgia[/name_f] [name_f]Therese[/name_f]
[name_f]Sister[/name_f] 2: [name_f]Susannah[/name_f] [name_f]Alexandra[/name_f]
[name_f]Sister[/name_f] 3: [name_f]Josephine[/name_f] [name_f]Noelle[/name_f]
[name_f]Sister[/name_f] 4: [name_f]Scarlet[/name_f] [name_f]Rose[/name_f]
Female Kidnapper: [name_f]Janet[/name_f] [name_f]Olivia[/name_f]

[name_f]Do[/name_f] you want more of a short nickname that the kidnapper’s give her? Because that (I believe) would be more realistic. I imagine a kidnapper would give a very short, to the point nickname for a girl he/she kidnapped just to call her–but if you’re talking about a fake name that they give her to be realistic, well that’s different. Here are my ideas, though.

[name_u]Rory[/name_u]'s Nickname (from Kidnapper): something based on physical appearance. Like [name_u]Red[/name_u] if she’s got red hair, or Spark if she’s outspoken/rebellious/a fighter.
[name_u]Rory[/name_u]'s twin: [name_f]Emma[/name_f] [name_f]Marie[/name_f]
Older sister 1: [name_f]Jenna[/name_f] [name_f]Clarisse[/name_f]
Older sister 2: [name_f]Melanie[/name_f] [name_f]Pearl[/name_f]
Older sister 3: [name_u]June[/name_u] [name_f]Helena[/name_f]
Older sister 4: [name_f]Janette[/name_f] (not [name_u]Jan[/name_u]-it but Juh-neht) [name_f]Delores[/name_f]
Kidnapper: [name_f]Flora[/name_f] [name_f]Gretchen[/name_f]

Sorry if these aren’t the kinds of names you’re looking for, I couldn’t really get a feel for your style of naming from the examples listed.