I think Bastion Bumblebee because of the car transformation and being the only one that actually transforms (ram too but not really), followed by Illari because of the distinct voice.
Here’s my ranking in video order (can’t post images so thumbnails as pictures)
By visuals, Rein. Distinct and unique looking
By voice, Illari. They NAILED how Arcee sounds in Transformers media.
If they actually tried with her face it would be Illari. The fact that they butchered her face like that and didn’t give her a highlight intro is just tragic.
Bastion and Rein are probably the best tho.
This collaboration would have been just as successful if Optimus Rein was the only skin. Actually, probably more successful if they allowed him to turn into a semi-truck when he uses shoulder check of justice.