Your Niagara 26 is a well built boat by a talented nautical engineer. Congrats.
The 9.9 Yamaha I assume is their outboard, and your controls for fuel and gear shift have been extended from the engine into your boat.
Switching sides of the boat is not a big deal.
- You will need to assure you have enough cable length to reach the location you choose.
- Secondly you will need to assure that the controls work as you intend.
- Optimum (usually) orientation means you throttle increases fuel flow when you push the throttle forward and reduces fuel when you pull it back.
- The control for the gear should also work in the same manner. Push forward moves the motor into forward gear.
Flipping the controls from port to starboard may impact the orientation. You will need to make the adjustments before securing the controls in place.