I think that you may be confusing the requirements for an ECM (executive committee meeting) with those for an EGM (extraordinary general meeting).
With regard to an EGM, there’s nothing in the NSW Strata Schemes Management Act (SCMA) about the date shown on a Notice of Meeting, but it does prescribe that Notice must be served on each owner at least seven (7) days before the meeting date.
Nothing is prescribed about that Notice being placed on the Owners Corporation’s Notice Board, although Notices of an ECM and the consequent Minutes may be.
In response to your point #3, Schedule 2 Clause 10(8) of the SCMA states:
(8) Voting rights may not be exercised if contributions not paid A vote at a general meeting (other than a vote on a motion requiring a unanimous resolution) by an owner of a lot or a person with a priority vote in respect of the lot does not count unless payment has been made before the meeting of all contributions levied on the owner, and any other amounts recoverable from the owner, in relation to the lot that are owing at the date of the notice for the meeting.