Happy to see someone who read through the analysis! I just looked back at your criticism and you make stone goods points. I did notice that almost all the negative effects are coming from the same citation in the study, so I looked into the study they are citing there. Here's a link to the PDF of that study.

The main take away for me from this study is that they were feeding the cats a "vegetarian human diet," specifically casserole mince along with a couple others. Feeding these cats a diet designed for humans is obviously bad, but it doesn't speak to commercial food designed for cats. You can use this to say that a homemade vegan diet is not good for cats. I've always said, don't do a homemade diet for your pets.

There were also negative outcomes from citation 30, but the full text is behind a paywall, so I can't really check on it. Of anyone has a copy I'd love to read it.

The studies that did use commercially available cat foods (literally all the other studies linked) found that the cats fed a vegan diet were within the range for regular healthy cats.

I am not making the claim that vegan diet is healthier. I am not claiming that you can make your own cat food at home. My specific claim is that there is not a statistically significant difference in the health of cats that eat commercially available vegan cat food. If you have a similar quality study to the contrary, please post it. Until that happens, I'm going to stick with the researchers who published the study, when they say:

Perhaps a take-home message is that use of commercially prepared vegan pet foods appear to be safe for use in cats and dogs but further research is needed.