I think Jess would be a cherished gift! I'd also include the 2006 catalog with Jess on the cover as a keepsake for her little girl.

The centerpiece is a great idea! You can purchase butterflys made out of pantihose and pin them from the ceiling on fishing line. OR you could attach fishing line to each one and hang onto long ribbons to use like streamers.
These butterflys are cheap to buy, but easy and cheap to make too! Their is also a link on HGTV on the Carol Duvall show to make butterfly mobiles by rubber stamping on acetate. The ribbon could be the inexpensive reels from the craft store that are like 2 or 3 for a dollar.
There is also an American Indian legend about butterflys that would be sweet to include in the invitations or at the party as little scrolls.
We attended a pageant where the girls were read the legend and then released live butterflys. Live butterflys can be bought via the internet and are pretty inexpensive, but I remember what a special time it was and how it brought tears to my eyes. The legend is something about whispering your hopes and dreams, wishes??? to the butterfly and then release it and the butterfly will take it straight to heaven.

I will look for the copy of it and send it to you. When I read your post, I thought this would be a very special thing to do at the shower to make her day even more special.

I will look it up and post again soon.