too similar?

Are the names Isley (eyes-lee) and Elsie (el-see) too similar??

Our daughter’s name is Isley (she’s my step-daughter, although I don’t call her that). When we hopefully have another daughter one day I would really like to use my grandmas name somehow, which was Elsie Yvonne.

She always went by Yvonne though. I knew her as Yvonne. Everyone called her Yvonne. So I’ve always said I’d like to use Yvonne as a baby girls middle name. But I am growing really fond of Elsie as a first name as well...

What do you think?