Names for Thumper

Oh man, Pat and I have been laboring (ha, ha) over these for some time now.  What name for this baby?  What name for this baby?

We've decided on Paul for a boy.  Now whether that's Paul _____ Rankin or ______ Paul Rankin, I'm not 100%.  Paul is actually my Grandma O'Brian's maiden name. 

For a girl, we're really struggling.  We'd like to use a family name and we've looked at the family trees over and over.  I guess I'm hoping I'm going to see something new each time?  The girl names in the running: Celia, Kate, and Lydia at the moment.  But having a complete name that we both like -- that's the hard part, and that's where the names are subject to change.  The whole name has to sound good -- it's what I'm going to yell when this child's in trouble.  :-)

Suggestions welcome!!