It could be morally good to return some grants if there is a good theory on how this will lead to better results for the people involved and their families, for the communities they are part of (primarily, the EA community), for society, and for the civilisation.
Some deontological motives and considerations could be a part of such a theory. For example, as other people already mentioned in this discussion, returning grants could send a valuable signal to the EA community and to society.
However, it seems to me, the framing of the question "Under what conditions should FTX grantees voluntarily return their grants?" hints at the possibility of some hard-and-fast deontological algorithm for deciding when grants should be returned. I don't think such an algorithm exists. The theories for why returning funds would be good should be far more nuanced, and applicable to very narrow strata of grantees and victims respectively (perhaps even down to individual grantees and individual victims), rather than large strata such as "all grantees" and "all victims", or even "1% of victims who were affected the most in terms of the portion of their net worth that was destroyed".
Considering the above, I think just returning money to FTXFF (or another pool of money) would be ineffective. And even creating a short-lived organisation to administer claims for returns from the victims will be ineffective, too (especially considering the opportunity cost for people who can quickly create locally-effective organisations of this sort: I believe such people have much more valuable things to organise, from the EA perspective).
I think a solution that could be low-investment and also relatively effective is organising a forum where individual victims share their stories and ask for help, and individual grantees can come and respond, assessing their own situation and the situation of the victim, that is, building "a good theory". And then publicising this forum among both the victims and the grantees. This also doesn't mean grantees should return their entire grants, they may help a little, according to their situation and the situation of the particular victim. However, one complication with this solution might be: how could the stories of the victims be verified?
In this setup, grantees should also consider the implications of their decisions for the community and society, not just themselves and the victim. While the latter are highly individual, the former are mostly shared. So it would make sense for some people who are experts in community strategy, sociology, and ethics to write a few essays on this topic that grantees would be advised to read before visiting the forum. (I'm not such an expert.) Of course, individual grantees would still be free to form their own sub-theory regarding these "high-level implications", according to their own understanding of the community strategy and ethics.
Good points. I think you're absolutely right that everyone will have to wait for the legal system to play out before doing any additional returns that are morally required (to the extent that legal clawbacks have not addressed the extent of funds that need to be returned).
However, I think we will probably have enough information to discern what is morally obligatory well in advance of when the legal system sorts out what is legally obligatory -- Madoff litigation is still proceeding over a decade after the Madoff scam imploded. If we know that returning $X is morally obligatory, then we know what the floor is. That awareness allows for a head start on how to deal with the situation. Early engagement with moral demands also shows that the community is attempting to grapple with the complexities of this situation rather than seeking to do the bare legal minimum.
I am not convinced that "Future Fund" is really that distinct an entity from FTX for taint purposes, since it seems to be a broad term compromising the FTX Foundation (whose board members were all senior FTX / Alameda people), DAFs linked to senior FTX people, etc. It is likely these entities had knowledge of the sheningans -- I am not suggesting that the Future Fund staff did, but the entities did know.
I think that taint is broken not by the number of entities, but by the recipient providing reasonably equivalent value in exchange for what was received, without reason to believe the money was tainted. Removal of taint requires not just clean hands but also action to the recipient's detriment that makes reversing the transaction substantially unfair. So, if FTX gave money to the FTX Foundation who gave it to a subgrantor who gave it yesterday to a charity for a project for which funds have not yet been irrevocably committed, I think all the money is still tainted. Likewise, if someone stole a car who gave it to my grandmother, who gave it to me, who gave it to my sister . . . it's still stolen property no matter how many times it changes hands.
However, if FTX gave money for a certain conference, and the grantee has held or irretreviably committed that funding to the conference, the taint has been broken as long as the grantee had no reason to know of the taint. It is no longer possible for the grantee to reverse the grant without causing a concrete loss to itself (as opposed to a loss of expectancy). Likewise, if the original thief sells the car for a fair price to someone who had no reason to believe the car was stolen, it is morally OK for them to keep the car. Someone has to bear the concrete loss.