If Firefish is going to come back, Kainoa won't have a hand in it. They quietly handed over the keys to the repo to a maintainer... who has publicly stated they aren't a programmer and are just looking after commits. Not exactly a signal things are starting back up.
https://git.joinfirefish.org/firefish/firefish/-/issues/10847
Unless there is an announcement soon about someone taking up development again, I think it's safe to say Firefish is over as a Fedi platform.
Optimism wants to say that someone will, but at this point even if someone does it'll be playing catch-up to the current state of affairs. It isn't possible for someone to come off of the street and say "I'll do it" and go back to the pace that was happening last summer immediately. (But it's not impossible for me to be wrong and six months from now someone does. I'm just not banking on it happening. Even the Firefish name itself might be too damaged in reputation to even take back up.)
#Iceshrimp, #Sharkey, and #Catodon are #Misskey derivatives who are continuing onward with things. All three of them are disassociated with FF completely so it seems Misskey still has a future with non-Japanese users. Server admins who wanted to consider a Firefish instance but shied away from the drama last fall may want to follow those projects instead.
If your fedi server is still on Firefish, don't be surprised if an announcement "were taking signups on our new Plombus server, in X months Fleeb will be decommissioned" comes down sometime soon. Internet services without recent updates are asking for trouble from exploits and vulnerabilities. Also, without an active FF developer to fix standing issues (or a skilled DB admin on your instance's behalf to whittle the database and schema to fit the new system as well as possible) a cut-over migration where users don't lift a finger isn't in the cards like the Calckey to Firefish migration last September. It likely will be up to you to decide to either move your account Mastodon style (no post migration, just your follower lists and a link back to the prior server) or to just start fresh.