but would rather name the baby after his/her grandpa Cary Lynn
Sounds like you already have the name. Lots of variations with that.

Girl:
Carrie-lynn
Carlynn
Carly
etc.

Boy:
Carl
Carlin
etc.

My daughter is named after two great-grandmothers, Eva and Jean = Jeaneva. We pronounce it like the city, Geneva. And while she loves her name and is very proud of it, she gets ticked off that she can't find mugs or pens or key chains with her name, lol.