Given the focus here on companies, rather than non-profits, I wonder if this should be framed in terms of investments rather than donations. It seems like the companies mentioned aren't easy to invest in. 

One option here is Agronomics. This is an investment company that trades on the London Stock Exchange, and has a portfolio of over 20 companies, including 5 that focus on precision fermentation (as well as several that are 'fermentation derived', and others that work on cultured meat):

https://www.agronomics.im/portfolio/

I don't know how this compares to donating to the Good Food Institute. I expect GFI's work benefits many more companies working in the sector by influencing government regulation. On the other hand, Agronomics promises a potentially large return on investment.

(disclaimer: I own shares in Agronomics)

I don't think we should care about biodiversity inherently. But it could be instrumentally valuable to protect large areas of nature until we have a much more detailed understanding of the species that are out there - and the potential food sources and medicinal compounds etc that could be valuable to humans and animals. My intuition is that the best interventions in this area will fall well short of the best interventions in other cause areas - but would still be a big step up from improving a basketball team!

If vegans do have higher rates of depression, it seems like there are several possible explanations:

1. It is indeed due to diet/nutrients.

2. There is a selection effect - people who go vegan are more likely to suffer from depression, but it's not due to a vegan diet. For example, perhaps people who go vegan are less conformist/willing to go against social norms, and this corresponds to a psychological profile that increases risk of depression.

3. Relatedly, it may be that going vegan is distressing because of seeing other people's animal consumption. This might not just be due to greater awareness of animal suffering, but because it creates a barrier between a vegan and friends/family/rest of society - i.e. the main driver may be social exclusion.

I've not looked at any literature on this - perhaps there are some studies which largely rule out 2 and 3. I expect it may be a combination of the explanations (anecdotally 2 and 3 are both true for me - I was anxious and depressed before going vegan. And veganism makes it harder to connect with some people, particularly e.g. when dating)

"there isn't much reason for many classes of vegans/vegetarians to experience increased rate of depression due to distress about other people's animal consumption: those who would identify health, environment, culture, some forms of religion, etc. as their primary motivation for their diet."

I agree this is likely for those where their own health is the primary motivation. But I could easily imagine that people who intensely care about the environment, culture, or their religion being distressed (to the point of depression) when they are surrounded by a society that widely dismisses and often mocks their values. 

This is a good point. I may be misinterpreting the cited research, but if the proposed training increases disclosures of CSA, that will (a) presumably reduce 'costs as a consequence' (which includes a monetised value of the physical and emotional harm suffered) but (b) plausibly increase 'costs in response' (due to increased police, prison, and safeguarding costs)

Considering that immigrants are also cheaper to the state than the native-born, and they outearn the native-born, migrants who arrived 2019-2023 will make a net contribution to British finances.

I do not think that the UK should restrict immigration for fiscal reasons. If the UK does choose to restrict immigration - as it seems inclined to do - it should be clear about why. It is not because immigrants have placed “public services and housing access… under too much pressure” and immigration threatens the welfare state. Rather, it is simply because voters don’t like it very much.

Your analysis seems reasonable. But it's plausible that immigration can both (a) make a net contribution to government finances and (b) place "public services and housing access...under too much pressure" (at least in the short-medium term). This depends on the scale of immigration, and the speed at which additional services, infrastructure, and housing can be developed. Some things can be developed quickly, but others might take decades (e.g. major new transport infrastructure). In recent decades the construction of new housing (and supporting public services) does not seem to have kept pace with the relatively rapid growth in population, mostly driven by immigration. 

I agree that we shouldn't only care about the perspective of humans. But if humans aren't around then much of the potential energy on Earth will simply go unused (unless another technologically advanced species evolves or visits Earth from elsewhere). So yes, this would be a waste.

energy can neither be created nor be destroyed, it is naturally a zero sum game

While energy cannot be created or destroyed at the level of the universe, this doesn't mean it's a zero sum game from the perspective of life on Earth. There is a huge amount of energy available in the form of atomic energy, solar energy, tidal energy etc that is simply going unused. If humans use this, no-one loses out.

The amount is related to the value by some constant, unless you’re implying a time factor

Yes, I and others have explicitly been saying time is a factor, e.g. see my 2 examples above and comments by others. The amount is likely not related to value by some constant. The value that a given amount of money can buy will vary over time. 

but as far as I can see, the timing concern is a red herring, as in my model the pump is already primed and wealthy enough donors are dying in week one. 

I'll be honest, I don't understand this point, or why it means the value of a donation won't change over time. 

I may just be misunderstanding. But I don't think there's much more to say on this, unless e.g. you're able to share your model on Excel or Google sheets.

results in more money per unit time donated within the population, that would seem to be more effective to me

This is still only considering the amount of money donated, not the value of what the money can buy.

No, I don't understand your point. The fact that some people are dying and donating now doesn't answer the question of whether people who are not dying now should donate or invest now.