Thanks for the input. Here’s my reply.
Gaaki’s rhotuka was one of the main ones I didn’t have a clear vision for. But sense her rahagah power was water floatation I came up with a water trap based idea. If you have a better idea I would love to hear it.
I also had 2 other ideas for Bomonga’s staff. 1. Could sense tremors in the earth to give him a sort of 3D view of his surroundings (think Toph from ATLA). However this seemed too much like his rahagah staff ability, so I scrapped it. 2. Could cause targeted objects to vibrate. This may be more practical, but if it were I feel it probably would have been used and mentioned in his fight with Kongu.
I thought telekinesis would have made Kualus even more useful in helping to lift the coliseum. That, and that his rahagah power acted like a form of tractor beam (although without the beam part), led me to this idea.
As far as having others’ rhotuka be less combat related, I looked to clues from the story about this one. Iruini tended to be more light hearted when it came to their duty, and clashed with the others on this point to eventually deciding to leave the group. As rhotuka are representative of personalities and other such traits, I figure the pacifist of the group would be more likely to be one of the only ones to have a helpful power. Besides this, I did consider this idea further, as I didn’t like having them be so combat related. So I thought of powers like water prison and numbing that could be used for helpful reasons like shielding and soothing pain.