If you need to be really, really quiet, there are some electronic instruments available – the probably best one is insane-expensive ($1850), eCorder or something like that, but the WARBL at http://www.warbl.xyz is just $250 – the tradeoff being it’s not specifically emulating a recorder, and thus doesn’t have the two double holes on the bottom (you use alternative fingerings to get those notes instead).
I also recently ran across this little snap-on piece of yellow plastic thing that interferes with the air coming out the top and acts as a mute, if you google “recorder mute” you should find it. No idea how well it works oh.