I agree that veg*n retention is important, thanks for writing this up!

Another reason for concern here is that ex-veg*ns might be a significant source of opposition to animal advocacy, because they are motivated to express a sense of disillusionment/betrayal (e.g. see https://www.reddit.com/r/exvegans/) and because their stories can provide powerful support to other opponents of animal advocacy.

Note that the Faunalytics study finds that a decent number (37%) of ex-vegetarians are interested in trying again in the future, which bodes well for future outreach to them and mitigates my concern above a little bit.

There's another very large disadvantage to speeding up research here—once we have digital minds, it might be fairly trivial for bad actors to create many instances of minds in states of extreme suffering (for reasons such as sadism). This seems like a dominant consideration to me, to the extent that I'd support any promising non-confrontational efforts to slow down research into WBE, despite the benefits to individuals that would come about from achieving digital immortality.

I also think digital people (especially those whose cognition is deliberately modified from that of baseline humans, to e.g. increase "power") are likely to act in unpredictable ways—because of errors in the emulation process, or the very different environment they find themselves in relative to biological humans. So digital people could actually be less trustworthy than biological people, at least in the earlier stages of their deployment.

Another potential application of an urban design background is in wild animal welfare: some aspects of city planning might predictably affect the number of urban wild animals living there and their quality of life.

I have some draft reports on this matter (one on longtermist animal advocacy and one on work to help artificial sentience) written during two internships I did, which I can share with anyone doing relevant work. I really ought to finish editing those and post them soon! In the meantime here are some takeaways—apologies in advance for listing these out without the supporting argumentation, but I felt it would probably be helpful on net to do so.

• Astronomically many animals could experience tremendous suffering far into the future on farms, in the wild, and in simulations.
• Achieving a near-universal and robust moral circle expansion to (nonhuman) animals seems important to protecting them in the long term. This is reminiscent of the abolitionist perspective held by many animal advocates; however, interventions which achieve welfare improvements in the near-term could still have large long-term effects.
  • But moral circle expansion work can have direct and indirect negative consequences, which we should be careful to minimize.
• It may become easier or harder to expand humanity’s moral circle to nonhuman animals in the future. Since this could have strategic implications for the animal advocacy movement, further research to clarify the likelihood of relevant scenarios could be very important.
  • I think it's more likely to become harder, mostly because strong forms of value lock-in seem very plausible to me.
• Small groups of speciesist holdouts could cause astronomical suffering over large enough time-scales, which suggests preserving our ability to spread concern for animals throughout all segments of humanity could be a priority for animal advocates.
• Ending factory farming would also ameliorate biorisk, climate change, and food supply instability, all of which could contribute to an irrecoverable civilization collapse.
• Preventing the creation of artificial sentiences until society is able to ensure they are free from significant suffering appears very beneficial if attainable, as developing artificial sentience at the present time both appears likely to lead to substantial suffering in the near-term, and also could bring about a condition of harmful exploitation of artificial sentience that persists into the far future.
• Moral advocacy for artificial sentience can itself have harmful consequences (as can advocacy for nonhuman animals to a somewhat lesser extent). Nevertheless, there are some interventions to help artificial sentience which seem probably net-positive to me right now, though I'd be eager to see what others think about their pros/cons.

In terms of who is doing relevant work, I consider Center for Reducing Suffering, Sentience Institute, Wild Animal Initiative, and Animal Ethics to be especially relevant. But I do think most effective  animal advocacy organisations that are near-term oriented are doing work that is helpful in the long-term as well—especially any which are positively influencing attitudes towards alternative foods or expanding the reach of the animal movement to neglected regions/groups without creating significant backlash. Same goes for meta-EAA organisations like ACE or Animal Advocacy Careers.

Tobias Baumann's recent post How the animal movement can do even more good  is quite relevant here, as well as an earlier one Longtermism and animal advocacy.

I also am very pleased that I'm the third James to respond so far out of four commenters :)

Pablo Stafforini has a great bibliography of articles on wild animal welfare that includes some earlier work coming from outside the EA space.