I'm really sorry, but I honestly mistook Keslee for "Kelsee" at first glance; I'm also not a fan of it (well, as first name, at the very least). I do like the sound of the potential nickname Kessie, to be honest. I'd suggest
Renee Kesley instead, because
Renee is already uncommon nowadays; I think
Renee would be refreshing. Then also, nobody would certainly ever guess her middle name, so that's another fun perk. I agree with
Justina and feel that she may correcting people for much of life, with Kesley / Keslee.
For a unique K name, how about the name Kella (I've heard it on a 96 year old woman, so I also know it has history)? Sure, she may also have to correct people who assume
Kelly or
Ella, but I think it's more doable. Are there perhaps any other names that you like?