A couple of quick thoughts:
If indeed Xdresser was referring to the Leap Manifesto (and he has not confirmed that he was – he has supplied no source as of yet) - then a quick search would have found a number of things:
1) The Leap Manifesto was not adopted as NDP policy – at least not to this date.
2) The NDP federally dealt with the Leap Manifesto after it was introduced at the convention reviewing party leadership. It was never – to my knowledge adopted as policy at any federal, provincial, or territorial level.
3) The authors of the manifesto (Klein and Lewis) described it I believe as an aspirational document not a policy document. As such it was signed by a substantial number of scientists, academics, celebrities etc. who did not express a particular party affiliation.
4) One of the naysayers to the document was Rachel Notley. You may recognize the name – a provincial NDP Premier – and the point here is that each provincial NDP party has its own unique voice and personality. Again the Leap Manifesto was an aspirational document presented to the federal party.
5) As for giving First Nations the veto over ‘every and all development in BC’ – although the UN has expressed grave concern over the treatment of Aboriginal peoples in Canada – I very much doubt that as a body the UN has expressed that particular point of view. I believe "the United Nations Declaration on the Rights of Indigenous Peoples" is considered to a 'universal' document not just pertaining to BC or Canada.
Suggesting that Xdresser was mistakenly referring to the Leap Manifesto certainly appears a reasonable supposition.
But then maybe he/she has a more reliable, verifiable source for the opinion.