I agree with many of your comments.
I'd imagine
Libby is a full name as it's popular here. I definitely agree that
Jack,
Charlotte,
Tanisha and
Amber is a mis-matched sibset. I thought Luciannie was odd and wondered if it was a typo but it could really be a combination of
Lucy and
Annie. Strange though!
Darcey Rose is probably my favourite combo.
I'm guessing Bluey is a nickname. I've encountered his name before in a previous BA. I'm assuming Lea-Jon is male although I agree that
Lea looks very feminine. Presumably it's a creative spelling of
Lee.