I get the movements you are talking about and, this will sound retarded but, for me it can be simply to different sounding grunts.
The hips at the start of the pull is a 'Hmmp' and the end of the pull is a 'Hrrrr'...
Yup, retarded. However...
Can you get the team on a set of rowers in the gym or even deadlifting/rowing side-by-side with light barbell/broomstick and have them do the two movements slowly as you call "one" (for the hip push), and "two" (for the pull)?
Then just change it from 'one' and 'two' to a "Hooo" and a "Haah" sound. It's not a word per-se, so it will not be hampered so much by cortex associations. You'll find the team might even start making the sounds as they do the movements and it might even help them entrain as a group (trigger -> breath -> movement etc).
I guess this is why you see these types of cues used in military and police, where the word has morphed into a simple trigger sound that can be barked by a leader/coordinator to get a conditioned response from the team members.
The 'hrmmmp' is perfect. We talk a lot about 'finding the post' at the beginning of the stroke, which is the significant resistance you'll feel with good timing in the boat--the erg doesn't replicate it all really, no matter what damper. I've used it for a few days now and it jives well. Oddly enough, just 'Hips!' takes care of all sorts of odd and intricate things that have to happen with the hands and handle coming up, blade moving down, body changing direction, all while facing backward. I need to find more stuff out on this. Makes me think of semiotics.