This looks really great to me. I have some thoughts, perhaps too detailed for the text of the charter which is more broadly written, but I’m adding them in case they’re helpful.
Re use of services — in areas where there are no public toilets, cafes should be encouraged to keep their toilets unlocked and to let non-customers including homeless people use them. Any public-facing business that denies this access does not seem to me to be in the spirit of the charter, while those who allow this access should be sought out and encouraged to sign up, because they are probably already in agreement with the Charter and they deserve that recognition. This could also possibly apply to other kinds of services.
Re voice and involvement — I think that homeless people should have a voice in every area of public life as we all do in a democracy, not just solutions to the problems that they face directly. The Charter doesn't exclude this, but it does present certain challenges when some ways of having a voice require a fixed address — it could be good to explore different ways of opening up participation that don’t require an address.
None of these are essential changes I’m suggesting, just thoughts.
The separate consultation regarding monitoring, accountability, and evaluation will be equally important.
Over all, this seems like a big step in the right direction that could do a lot of good.