That is sad to hear that mander hasn't come back yet - I guess it's still waiting to see if something can be resolved, since the backups weren't recent.
But it is even more sad to hear that Rimu's community migration tool isn't working, on other instances without his direct involvement. Some of what you said makes sense to me though, like a community "owner" must be located on the instance where it is housed - if that were not the case then the system would be vulnerable to all sorts of spam where any bot could spin up communities on any instance, so some level of accountability must be maintained.
I suspect the official PieFed app will be Blorp, just from the way that Rimu talked about it iirc. It's chief competition is Interstellar, although that was designed more for Mbin with PieFed just being thrown into the mix.
The need to support FOSS is partially one reason why we aren't growing, and I don't mean the actual funds, but the enormous complexity of figuring out who to send them to. Dessalines & Nutomic? Rimu? PyLova? Voyager? Blorp? Perhaps at the end of the day it does not matter as we had fun in contributing to the development of the Threadiverse overall, but to new joiners it's definitely very daunting - it's far easier to pay Reddit and then get Reddit coins back in exchange. Though arguably less profitable when it merely buys you the chance to argue with bots. Yet.. an enormous fraction of our own traffic here are reposting bots, often from Reddit, so is this truly "better", enough to convince some of them to make the switch? That's the rub - they would be buying into the future, just as Reddit kept telling them, and likely still tells them now (Reddit-trained & integrated AI will be so great...).