Yes.. an Owner can submit a motion to rescind or amend a resolution taken at a previous General Meeting, and the motion to do that would need to be submitted in writing to the Executive Committee Secretary within a timefame that would permit him/her to include it on the Agenda, and then distribute that Agenda to Proprietors 7 days before the date of the Meeting.
Yes.. an un-financial Owner can submit a motion, but they cannot vote on it at the subsequent Meeting unless they are then financial (i.e. on the day of the Meeting) unless the motion being voted upon is one of the few that requires a unanimous resolution like terminating the Strata Scheme or rescinding an Exclusive Use (Special) By-Law.