For some reason, and unlike most regular monsters, the cube jellies only have freeze varaint while the lichens have the rest (fire,poison,shock)
I dont know why they chose to do that,but this is a simple excuse to bring 'new' levels and monsters.

Poison cube could be absed of the green giant and mini of RJP and its specialabilty would be leaving mist while he moves (like a toxilargo,butlast for shorter time)

Fire cube could melt into a big oil patch.T3 version will drop blobs like the blast cube, but those will cause fire,igniting said oil.

Shock cube can charge towards the enemy, similar to a quicksilver but in a staright line, leaving a small impassable shock trail.On T3 they will do this attack twice, making an "L" pattern. If some of them gang up on you they could trap you!

Fianlly,no special ideas for the ice lichen, except it could throw snowballs instead of spines.