I'm inheriting a cat (long story) and did some basic research into the possibility of a vegan diet. It seems that while it is possible, like your links suggest, there is no easy way to do it. I looked in thr local stores and while I have found vegan food for my dog, they don't have anything for cats. A few online specialty places but the food is so expensive it is off the table.
I've switched to trying to find the lowest impact food but even that information is hard to find. I hope that it gets better and this small market gains traction, but it's not really at a level right now where thr average person can make a switch.
I haven't seen this brand locally but it does look decently priced. I don't live in the US but I do see a couple specialty stores in Canada that can ship it. I might give it a try. Thanks for thr recommendation :)