At least 4 of those are black powder guns.
The single action just might be a cheap air pistol.
Yes, those narrow slots in the cylinder look wrong.. CO2 pellet pistol, maybe just a cap gun.
The large relic two spaces to the left of the "Colt" is interesting. Looks like the remains of a Deane & Adams or Beaumont - Adams piece from the Victorian era. Mid-1800s. Pity most of the parts are missing.