Ahhh, the vapor ware of the 1930's. The bus would be too heavy with those tracks (which presumably are not rubber) so they would likely sink into the mud, and it's a good thing they have an emergency way to release the passenger cabin to return to the surface. The "bicycle" is not a bicycle when it has 6 wheels, and unlike other wheeled water craft appears to have no cleats on the sides of spherical pontoons. The seaplane with wheels would be ok, but wheels need brakes, and brakes don't do well when submerged in water. The tank with hemispherical wheels does have cleats, but the cleats don't provide a lot of traction on land and also seem to be aimed as solving the next-to-non-existent problem of tanks tipping over laterally, which just about never happens anyway. The arctic air-boat/sled was probably the only even close to practical device (aside from the LTV which was real). However the arctic boat would do better, these days, as a rigid inflatable, and or a hovercraft.