I bet one of the 5's is a civil defense siren, the 5t (possibly) is probably the fire siren, so it can do a different signal, the 2001 is probably the replacement
Not sure what this is, but it looks like a lot like W.S. Darley to me. https://www.google.com/maps/@41.1565253,-99.1550161,3a,22.3y,350.88h,103.81t/data=!3m6!1e1!3m4!1svuVIdeODIEK9mnPOqFkL7A!2e0!7i13312!8i6656 It's a Darley Champion missing the other chopper/stator. I like the T-Bolt in the backround