Yippee!!!!
That's great news. My standard advise is 'just do it' and don't try and make it perfect. It seems like your video idea is perfect and yes, go ahead and let her talk aloud about her thought process of how she figures out the illustrations.
(I don't know anything at all about what is age-typical, but even if it is age-typical, she is probably going about it in a gifted-typical way.)
Remember that you don't hurt your chances by not having the achievement testing. In the long run, they'll just ask for it if they need it.
Smiles,
Grinity
