Character Animator - Replaced source AI file results in missing mouth (rig and record mode)

Hi all!

I'm new to the program, but I have been successful in creating my first puppet. My issue is now with revisions.

The client I'm working with wants to switch out the character's clothing (I am working with an artist remotely, so I wasn't able to go into the original AI file myself and do this.) We decided to replace the source artwork in the top right corner of the Rig mode screen. The dimensions are correct, so the rigging of the arms, legs, and walking motion in record mode seem to check out. The issue lies in the mouth - the mouth has completely disappeared in rig and record mode even though the layers do not seem to have changed. 

To add - I created a 'Standing L' and 'Standing R' layer by duplicating the left and right profile for the original walking feature. These layers are now missing serious parts of the puppet. I'm not as worried about this as I am about the mouth/ saving time rigging.

I have checked the AI file, eyeballs on/off, and did some research online. I'd be so appreciative if anyone could lend an idea or suggest a more seamless way of replacing source artwork in the future. Attached are two screenshots of the original and replacement.

Thank you so much and all good things!!