They are in the Production Zone to the far right of the island. You will have to collect the Dirty Beaker from the Museum and then use the Drawbridge key to cross into the production zone.
(see related question)
The monsters on Steamworks are all mutations of plants on the island. They took over the island after being altered in the Research labs (Production Zone) to the right of the Hub. You battle them at several locations on the island. (see related question)
on the top right when you enter the island
it's across the drawbridge
It is by the "tightrope" vines at upper left past the Living Quarters. The only way to get there is through the quarters using the key, which is in a closet all the way across the island in the Research labs. (see related question)
its in the museum on mainstreet of steamworks island :)
you break it with your rubber mallet.
if you go to the right you will see a place to put the dirty beaker
It's Steamworks Island #14th Island
(The solution is at the related question "How do you beat Steamworks Island")
the crab on steamworks island is next to the living quarters
You go to Steamworks and head to the museum and there is the Deogen
steamworks island