For System and Frame breaks, go to Engrave mode and in the left panel click the unlock layout button - that’ll clear them all.
For resetting properties, go to Write mode, ensure that all signposts are turned on (from the View menu), Select All and use Edit > Reset Appearance and Edit > Reset Design.
You’ll still need to reset beaming (which you can do with everything selected).
Oh, and from the Engrave menu, the three resets at the bottom (for Staff Spacing, Note Spacing and Lyric Offsets).