Hi there,
i'm currently applying jetpack joe style coin for my game as well.
i didn't use object pool.
so i put like 20 coins in my hierarchy, and i parent them all under coinMoverObject.
The idea when the coins already outside the screen,then they will respawn with another form.
So my trick is use "array maker" action and have bunch of shapes like stars,heart,etc.
Then i use "array list get random" action to randomize the shapes that will spawn.
And this is the most boring part ever, for example when the "star shapes" got picked, i use the set position for all 20 coins. so i arrange the coins into star shape on the scene and i copy paste the x and y coordinates for each coins. and i have almost 20 shapes. so do the math
Hope it helps.