I think you could probably argue that ethical veganism is a deeply held belief that humans are not inherently superior to other animals, and that said animals also have emotions, etc.

This would address 3 as it would definitely govern one's conduct and practices: not exploiting animals in any way.

I would also argue that it addresses ultimate questions about human's place in the living world, partially addressing 4.

Also, looking at federal law (https://www.justice.gc.ca/fra/sjc-csj/dlc-rfc/ccdl-ccrf/check/art2a.html), looks like "liberté de conscience et de religion" should be interpreted widely:

La « liberté de conscience et de religion » devrait être interprétée largement et s'étendre aux croyances dictées par la conscience, qu'elles soient fondées sur la religion ou sur une morale laïque et les termes « conscience » et « religion » ne devraient pas être considérés comme tautologiques quand ils peuvent avoir un sens distinct, quoique relié.

So Ontario's interpretation here is potentially unconstitutional, especially if their decision hinges on something as minor as what a belief system has to say about a Creator.

EDIT: Not a vegan at all, but I can understand the ethics.