I dont think you really need to run the car hot so that the themostat is open befoe draining.. just open the drain plug and let it drain out that way.

Yes I do recommend to rreplace the thermostat, if its never been done and your car is a 1998 (as per your screen name) Id say do it, just to be on the safe side. they dont cost an absurd amout of money, and you will have the coolant removed anyway.

yes, you brought up a good point Marco.
Its a good idea to have your climate control set to defrost (max heat, to help bleed the complete cooling system) sorry I forgot to mention that.