Do you have any actualy proof of this? It just seems like your own speculation. Considering the eye design looks like the Yoshi transformations and not enemies', I think it is logical to conclude that.
It's just too obvious.
The transformations of Yoshi are Mechanical Structures, based on movement on Ground (Car), Air (Helicopter), Underground (Mole), and Underwater (Submarine).
The most logical reason why Airplane Yoshi was dropped out from the game, was because there was already a transformation meant for flying.
Just because the eyes are like Yoshi's, doesn't mean that they are Yoshi's Transformations.
The Shyguy, Tweeter and the Bob-omb are also in the same Graphic set. Maybe originally there was going to be Shyguy Yoshi and Bob-omb Yoshi?
I doubt it. Therefore leading to an obvious conclusion, they are enemies.