Most toilets don't come with a wax ring or flange bolts, so you'd need those. Dpending on their age, you may want to replace your shutoff valve and should replace the hose.
Style is the biggest determination of which Toto you get.
Because modern toilets do not empty the tank, there is (normally) some room-temperature water in the tank to warm up the incoming, so unless the toilet gets several flushes in a short time (essentially emptying the room-temp water with all cold), condensation isn't as big an issue as with older designs since the water will usually stay above the dew point. If you think it will be a problem, best to buy an insulated tank, but it isn't an issue for most people today.