Question 1:
Maintain frequency is preferable to volume when cutting. I wouldn't necessarily reduce either, frankly. But if you had a choice between 2x everything, three times a week or 3x everything, twice a week, for muscle preservation purposes I would choose the former. Maintain the acute stimulus, and you burn less per workout (less catabolic processes). You'll also feel the effects of volume more deeply when you're cutting.
Question 2:
Don't SD, just keep working out at your 5RM, when you finish cutting, SD begins.