Yes. One of the major advantages of building your own boat is that you can customize your boat to fit your preferences.
To change seats or lockers size or location is easy but beware of hull and structure changes or scaling. They may have unexpected consequences.
Keep some important points in mind when making changes:
- the structure like bulkheads and stringers spacing must be respected
- you can not change the materials specifications: the boats are designed with a safety margin and are strong.
- if you add or move components, try to keep the center of gravity as designed and the weight within reasonable limits.

We will design some modifications or changes if we feel that other builders may be interested but if you modify one of your plans yourself, you are on your own for all the calculations.
If you consider major changes, it is often easier to start with another plan closer to your requirements. Ask for a new plan on our message board and we may respond that we have one in the works.