There will never be a consensus on what it means to “be’ Indigenous or what the qualifications are for someone to claim that they identify as Indigenous. So when we consult “members of the Indigenous community” who are we talking about?
That is the crux of the problem, isn't it? In other areas like sexual orientation or gender identity, there's a decently broad consensus that we should allow people to self-identify. The benefit of self-identification is that it discourages gatekeeping. One downside is that it doesn't change the fact that the broader community may still reject a person's self-identity. See for example the debate surrounding trans women in sports.
The issue becomes more acute when being perceived as a certain identity comes with some privileges, whether informal or sanctioned by our government. When that happens, it creates an incentive for people to self-identify in a way that they believe will benefit them in some way or another.
I don't have a solution. Just rambling.