What were her stools looking like before she started the Creon? That is an important factor to consider in looking for changes now that she is on Creon.
If she had greasy stools before- oil separating from the rest of what is in her diaper, a shiny/greasy look or feel to the poop you should see a decrease in this. If stools were very, very frequent you may see a decrease in this- hard to tell, since babies can have several a day and still be 'normal' esp if breastfed. If they were very loose, they may firm up some- again, you don't want hard stools, but you should see an improvement in appearance.
The most important thing you will be looking for is GROWTH. Some babies will rarely have what looks like 'normal' poop, but when started on enzyme therapy, it's clear it's working because they start to grow and if they've been having belly aches, gas, etc these symptoms improve. Within a few weeks you should start seeing gain- the dr should be having her in for regular weight checks to monitor for this. Wishing the very best!
What testing has she had at this point? They will generally order a sweat test, genetic testing and look for results of her newborn screening. I hope she has a definitive dx soon so you can get her the care she needs at an accredited CF center.