In a nut shell, yes and yes.
Rule 28-600(3) permits having more then one air curtain on a single disconnecting means.
Rule 28-602 describes what is permitted as far as a "disconnecting means" is concerned, and no, a three position selector switch is not adequate.
Rule 28-604(5) requires that the disconnecting means be located within 3m of the equipment and in clear sight. I would consider this equipment to be "air conditioning" equipment because of the heating element.