The purple bike frame belongs to someone called Sonny IIRC, he joined and started painting it as a project then disappeared. I imagine he’d come to collect it if we have contact details for him.
In two minds about @mongoliandingbat’s bike/deathtrap. It’s a great example project, and is nice for showing off to newbies on tours. If there’s space to exhibit it (suspended from the ceiling? :D) it might be nice to keep, but at the same time that might be cheating a bit as it wasn’t actually made here?