Hello there, I'm indeed open to work on this as a paid work. If you join forces you should make sure everybody involved agrees on the same requirements ? Please contact me as described at https://clarkwinkelmann.com/flarum#extension-development if you wish to discuss and estimate a requirement list.
If you want to do this with me please have a single contact person discussing with me, I can't handle discussing the same requirement list with multiple non-connected people ? I'm happy to make suggestions here on the forum however.
Thinking about gwillem description. Why, instead of making this "guest" posting, just integrate registration into the composer and remove email verification ? The only field to add would be a password field and you could both register and login via the composer box itself.
Email-less guest posting would probably be different in multiple manners. Having both email and email-less guest posting in the same extension might not be the most straightforward implementation.
Some questions unanswered here are what should happen in a user does register with that email address later ? Also in the case of email-less usernamed guests, what rules do you expect to prevent/allow guests to reuse usernamed ? Also what should happen if a user want to register that username ?
