will you can use the shape key,s instead of ringing the face, because ringing it might be difficult , shape keys is just as modeling changing the the face element,s from point 1 to point 2 as modeling , search for shape keys it awesome
If it’s only for instructional purposes, a simple linear transition from one shape to another (with shape keys as said above) could suffice. But if the research project is about recognizing emotions and subtle face changes, it’s a lot harder.
You’d need a really goody artist to get out of that uncanny valley if you want a realistic transition. That kind of animation is done mostly with motion capture.
I could help with the first, but for the second you need someone with motion capture experience or software that handles it for you.
Honestly though you’d probably be better off with stock video footage, which should be easy enough to find.