Rollerbuddys I am quite sure are just an early version of what we got in ep1, with alyx using the reused idea for the rollerwand to control them. The rest are most likely just states to switch to when in certain sequences, isnt there a part wher rollermines burst through a barricade? those I would imagine would be the cut npcs, which would in every other way be the same as the normal ones, but fun to speculate anyway