that's incorrect on the draw step assumption...
you can play abilities during the draw step...
The action of drawing as per rules - does not use the stack, but drawing doesn't end the step - both players have to pass priority for each step to end... Most of the time this is overlooked, and players don't ask - but if you have abilities or spells you want to play - you can back them up(relatively speaking) to the draw step if they do not give you the chance to do something then...
so you can lock someone down with funeral charm and scepter, during the draw step, unless they have instants to play...
(Ebony Charm doesn't cause a discard...)