I think there is a fourth possibility, which may be a variant on your second one: ECNI foresee lengthy legal challenges about the application of the WF if they apply the SC definitions without further clarification (since the SC obviously didn’t consider the WF as not relevant to the EqA) so are wanting to pre-empt this and seek to manage the legal process in a way that leaves them in control of it, rather than waiting to have the terms set by those opposing them. And they are also drawing in all other legislation that refers to ‘men’ and ‘women’ to ensure no one can say “oh but this only applies to the SDO, not to FETO etc’.
And actually having read the whole 66 pages, as opposed to the press release, which I confess is all I had read yesterday, I retract some of my initial exasperation. I think ECNI may be playing this more cleverly than I gave them credit for. [But I stand by what I think is obvious about the SDO and the NIA98.]
i also like the clarity of their interim suggestions on toilet/changing provisions (do proper universal provisions, or do a mix of single sex and universal provisions) and their descriptions of what would constitute discrimination on grounds of transgender status and philosophical beliefs.
In response to PP, I am not sure that the issue is so much about whether ‘man’ and ‘woman’ mean different things in NI/RoI law as whether (a) this is an issue that specifically relates to the GFA (I don’t think it does for transgender people) and (b) a person in NI (say a woman or a transgender person) has had their (actual) rights diminished post-Brexit compared to pre-Brexit (I don’t think they have).
I was interested to see reference to the text of the GFA drafts having changed from ‘sex’ to ‘gender’. Having had some involvement in this area, I am morally certain this was a “we use more genteel language these days” move rather than a specific effort to go broader than biological sex. But others will no doubt give more authoritative opinions in due course.