Blowing white smoke can also be a sign of worn-out spark plugs - don't ask me how I know
If your timing was off, it'll make the engine run ragged, which can also cause white smoke, as not everything is burning efficiently, if you will.
The timing belt tensioner is a normal wear tear item on these 3.2L's, if it was not changed at the time of waterpump replacement, it's no surprize that it's failing now.
Word of wise for the future, when replacing waterpump, or timing belt, ALWAYS replace the waterpump, timing belt and tensioner at the same time, these can be labor intensive engines and it's just easier and offers peace of mind to do it all at once.
I've recently learned myself, that when a waterpump starts to fail, it can cause the tensioner to loosen and allow the belt to skip teeth. Mine did the same, but only by 1 tooth.
My engine was not damaged, and I truly don't believe your's is either. But, if the timing's off, it could lead one to believe there is serious damage, and word of wise, the timing belt tensioner, when it starts to fail, sounds like a rod knocking. Many mechanics mistake this for major engine failure.