That Hoover 900 series is very, very rare, as is the Kirby 1C and the Vacuette (I have both). The Kenmore with the dual headlights is also highly desirable.
That upright with the two lights is one scary-looking monster of a machine! I can't imagine the nightmares it must have caused for little toddlers living with one of those hidden in a closet! :-(
Good luck with the sale - these are definitely vintage vacuums.....