The topics that @tchambers suggested would fit right in, and it would be largely up to you how you'd like to structure the session. E.g. it might be interesting to compare / demo / discuss the different approaches to building alternate Mastodon UI side-by-side. Or ... up to you!
Other than our speed demo track, we use an unconference format optimized for online interactions, which means that attendees determine what sessions happen, and the format of those sessions, which run from presentations with Q&A to collaborative problem solving, plan making and open discussion. For how this looks like in practice, look at the notes from a previous FediForum, e.g. https://fediforum.org/2024-03/
With FediForum, we are trying to bring the Fediverse community together for a few days of live discussions of whatever needs discussing to move the Fediverse forward. Next week is the 4th time we are running it. We have a diverse audience, from plain users-for-personal-purposes to developers, operators, journalists, various organizations, moderators etc. (cont'd)