Yay it only took 2 years for someone to post a reply!! :-D
Thanks for your comments. I can't remember at what stage I decided to make our alien trader friends give out some useful hints - originally I had planned for talking to Zero-Bit to be essentially a hint system, but because the voice actor was unavailable during production decided to make it impossible to communicate with him whilst on the planet's surface, so I needed to add some extra pointing.
About the final puzzle, I had in mind that you had to send the chair out of control without triggering its automatic safety mechanisms, I had a lot of trouble communicating this to my co-dev so it was probably only clear in my own mind :-o