Esmae Emilie or Esmae Emily is lovely. I normally prefer Emily, but the other spelling looks lovely with that first name.

Other combinations could be:
Esmae Rose
Esmae Grace
Esmae Joy
Esmae Pearl
Esmae Edith
Esmae Ruby
Esmae Susannah (Susannah means lily)

Does Isla-Mae have a middle name or is Mae her middle name?