If the past is anything to go by negotiations usually take about 12 months before the first vote is held. The first meetings are always exploratory rather than specific. The union has a list of priorities from member surveys which they will work into specific claims over the course of negotiations, but any specific claims logged will remain in confidence until an agreement is reached so even those negotiating won’t be allowed to reveal them.
It would be unusual to enter a negotiation without a log of claims and there is zero problem with disclosing them - unless you want to spin whatever deal you get as a victory.
A member lead union should be keeping the members informed of what is going on in the room. Keeping things behind closed doors (outside of business confidential costings etc) only benefits the company ... and potentially a union leadership not interested in representing the membership.