This spelling seems like taking the long way around. It's just about guaranteed that other people will never pronounce nor spell it correctly, and you're dooming the poor child to a lifetime of having to correct others.
Lindsey is nice,
Gillian is okay but I would argue in favor of spelling it w/ a J for the same reasons as Ciorstan/Kirsten. Ditto for
Isobel, which is a pretty name but one of the rarest spelling variants, again dooming the child to forever having to correct others. I would go for
Kirsten,
Lindsey,
Jillian and
Isabelle.