Tacky to use niece’s middle name?

Hi everyone,

My husband and I found out we are having a little girl and I really love the name Lillian. It was my great grandmothers name. But hubby is concerned that it is his niece’s middle name. She was only born 6 months ago.

I have loved this name forever and disappointed to lose another of my favorite names (originally wanted Charlotte but that’s my niece’s name).

Is it tacky to use niece’s middle name as our baby’s first name?

If we do use it, should we ask his brother if we can (as it’s his daughters middle name)?

Thanks!

UPDATE: we asked the parents and they are thrilled if we use it :) Yay! Thanks everyone