Yes, I would use it.
I don't think
Olivia sounds all that similar and it is only your daughter's mn.
Though there are 2 in your church, it's still not in the top 100 and hasn't been so it's not extremely common.
Your husband's aunt having the same name would just be a happy coincidence. No reason for concern.
Lydia is the best out of the three. It's strong and classic.
Liliana is a bit frilly and
Leah is just sort of boring.