My work had them out a week ago or so, and I do think they're Fruity Pebbles. But whatever the case, they did taste really fruity.
To me, when I first bit into one the flavor was unmistakably that of Fruit Loops, but Fruity Pebbles is as likely a guess. I liked them, though.
Well, I don't know what mystery Oreos are...I don't think we have them in Australia (I've only since original, chocolate, strawberry and peanut butter) but since everyone else is saying Fruity Pebbles, I'll go with that too