4x10x3-ish freight hopper: I searched "duplo hopper" in BrickLink but only got this
2x2 brick with axle(?). The axles are hollow up to the edge of the brick
2x2 blue dome brick with eyes and a clip. The studs are hollow
5x5-ish dome bricks with a 2x2 centre. They have two tiny holes in the bottom, and a groove at the top. Initially I thought they belonged with the tube system pieces because I have several of those, but the circle size is too big for that.
None have dates on them.