Was the coolant by any chance some air working its way out? I've found the level will stop an inch or so in the days following any coolant system work, even bleeding it before hand. There's always a couple small bubbles that work their way out over the course of several drive cycles.
White smoke on startup is rather puzzling, as these vehicles have a dry intake. The only place coolant can possibly interact with combustion is through the head gaskets. If you have a concern of anything making its way into the combustion chamber, pull the plugs and take a peek in there with a boroscope. Any problem cylinder(s) will show up quite clean and free from the normal layer of carbon. Clean, in this case, isn't good.