I think I know a thing or two about cleaning teeth.
It does not matter if one brushes or flosses first. Bacteria can still be removed with calculus present, though the amount and location of calculus makes a difference in this case. Bacteria cannot get under calculus because calculus is adhered directly to the tooth surface.
A scaler that one buys at the drug store will not remove calculus because it is too dull. Also, a "professional" scaler will soon become too dull to be effective unless the user has a sharpening stone and knows how to use it. Anyone who uses a scaler in their homecare routine is likely just burnishing calculus or worse, removing cementum.
Over the counter mouthwashes do not clean teeth. Only disruption of the biofilm will remove harmful bacteria. Everyone should just save their money and rinse with water. Unless, of course, you like the taste and it motivates you to spend more time on your oral hygiene routine. Chlorhexidine rinses are another story....