A rank ordering of harm caused by man to animals

After listening to Peter Singer's  Animal Liberation, reading and some of the works of Tom Regan, and listening briefly to Gary Francione, I decided to come up with a rank ordering of decreasing level of justifiable harm to animals with 1 being the greatest harm. Briefly, the views of the three which are more sophisticated and nuanced than can be summarized in two sentences like I do below are

• Peter Singer:  He is a Utilitarian and for him use of animals is not problematic so long as they dont feel pain and can be used to derive benefits for humans even if the animals themselves go uncompensated for their exploitation.
• Tom Regan: He gives a more deontological rationale that animals like humans are an end in themselves and should not be exploited. For him animals have rights. If this is the case, then using animals without their consent is exploitation which basically means we cannot use them for any human ends.
• Gary Francione: Humans don’t have a moral justification for using animals irrespective of how we treat them

Ranking of harm to animals by humans

1. For food - slaughtered for meat after spending entire life in captivity in terrible conditions - caged livestock
2. For leisure - hunted as game
3. For scientific research - for medical research
4. For scientific research - for non-medical purposes - food and cosmetics
5. For transporting people and goods
6. For food - slaughtered but raised in better conditions - free range 
7. Indirect harm through habitat loss - deforestation, roads, shipping, land development, increase in flooding and wild fires caused by human activity
8. Indirect harm through pollution - pollution of air, soil and water. 
9. Emotional harm through isolation - in public zoos and parks  and as pets in private homes 

I have two distinct harms when used for food and rank one much worse than the other and also rank some harms including being used as beasts of burden worse than slaughter when it is done after allowing them to lead a not so cruel a life. I also have one type of killing for food as less unethical or less harmful compared their use for scientific research. My reasoning for this is even as the benefit of scientific research might be greater and in an utilitarian sense greater, the harm to the animal undergoing testing could be much greater as it has to live through the pain and suffering while it is being tested, which seems more cruel than quick slaughter. On the other I put hunting for leisure, which also might be a quick death as worse than that because it is being killed for fun and in a utilitarian sense, I feel this is worse way to derive pleasure than satisfying one's hunger for eating meat. I also rank the harm from pollution as quite low relatively. Therefore to me, while climate change is going to have a big impact on animal life, to me it does not rise up the direct harms I listed as higher. I rate emotional harm from isolation when they are kept in captivity in zoos or as pets in homes as the least based both on the assumption they are treated the least badly in this context and cared for reasonably well although emotionally they might be in the same state as in a testing lab.  

Do you agree or disagree? How might your ranking differ? Beyond being vegan what else do we need to abjure to lead a life where we dont end up contributing to animal exploitation. Would you go to the extent of foregoing life-saving drugs?