Re: pass phrases, my go-to for projects like that is to put a unique hash or something in the URL for each different person. The experience for users is that there's no password to remember or anything like that. They're not going to remember the URL anyway.
You can put the hash in a #xxxx part of the URL so it doesn't show up in logs if thats important to you. The downside is you need to give everyone their own URL (maybe via a QR code on a paper invite). But you already had to give everyone a pass-phrase so whatever :)
You can put the hash in a #xxxx part of the URL so it doesn't show up in logs if thats important to you. The downside is you need to give everyone their own URL (maybe via a QR code on a paper invite). But you already had to give everyone a pass-phrase so whatever :)