All other devs jumped ship. I think both Iceshrimp and Sharkey were launched by former Firefish devs (at least one of them was, Iceshrimp being a former hard fork of Firefish which was quickly rebased into a more up-to-date Misskey soft fork

Iceshrimp (Misskey fork) did not rebase their version of Misskey. They're still based on the same Misskey v12 era code from Firefish and there's no interest in significantly updating the JS version (as it'd make migration harder) now that the rewrite is well underway and (in my potentially biased opinion) quite promising.

[...] This is far from done which means it’s even farther from being daily-driveable.

If you're on a single-user instance, and can limit yourself to apps targeting the Mastodon API, it's quite usable. The web frontend still needs a fair chunk of work, and moderation tooling required for larger instances are still not there yet. (But there's enough to fend off spam)

Iceshrimp was designed for stability which is also why a number of Firefish features had been kicked out. It itself is on maintenance for as long as it will continue to exist, which won’t be that long.

The only features kicked out from the Misskey fork were, from what I remember, post imports (which were broken and leaked DMs (Sharkey's on the other hand should work fine, as their implementation is unrelated to the Firefish one)), and the centered view in the web front-end. The rewrite may end up removing more features, it's still not exactly clear as more important foundational work is needed before decisions like that can be made.

Sharkey used to be the king of features, but at the cost of reliability. Especially Sharkey’s Mastodon API implementation is infamously bad. The Sharkey community has been waiting for someone to step up and develop a completely new Mastodon API implementation for Sharkey for I don’t know how long.

Sharkey's Mastodon API was I believe more or less a direct port of the old Firefish one. (And, yeah, it's not in a pretty state right now.) Firefish's implementation has since gotten replaced with the implementation from Iceshrimp some time after Firefish was handed off to Naskya (which may just be the only Mastodon API implementation on Misskey-based software that actually works).

Also, the Sharkey devs lost a whole lot of community support when they collected donations for a server for Sharkey purposes and then took the money to set up a Minecraft server. Make of that what you want.

This is way too much of an oversimplification that I would plain remove this claim altogether. All I can say is that Sharkey/transfem.social has had a change of ownership and things are more or less resolved now.

And then there’s CherryPick. AFAIK, it’s a Japan-based Sharkey soft-fork in which a whole lot of Misskey and Sharkey issues have been fixed; don’t ask me for details, I only know this stuff from hearsay. Basically, CherryPick is Sharkey in good. Or in better.

CherryPick is older than Sharkey, and Korean (from what I know, anyway)