If that fleece is thick enough, and the shirt is long sleeve that should be enough. But don't come back and swear at me if you get cold!
I myself would take 4 layers--counting a short-sleeve T-shirt.
As for water, I dip and drink - untreated, myself. At Trail Camp, I go to the inlet stream of the pond, not the pond itself. Whether or not you filter or treat is up to you. Be sure to carry 3 liters above Trail Camp.