> understand and propose ways for poor people to live on a vegan lifestyle when $$$ is tight and calorie intake needs are bigger

That is a lazy excuse - literally the cheapest diets are vegan. Rice&dal will give you both calorie intake and protein at a cost of less than a dollar a day (which is why a lot of the world's poorest people subsist on it...).

> start prosecuting companies with large carbon footprints

Prosecuting? On what legal grounds?

Easier solution. Companies will immediately stop doing it if emitting carbon gets more expensive than not emitting it. Simple solution, carbon tax.