I have matched stains on several different boats and other projects. It used to be that if you asked nicely, a paint store would give you a small squirt of several different pigments. Now, it's easiest to just buy several cans of Minwax stain and mix it via trial and error. Stay away from the water based stains - you need the golden hue of oil base. Speaking of which, the golden hue of oil based polyurethane adds some age to the final product.
Repairing water damage is difficult. You may want to try a dilute solution of oxalic acid to restore the color to new/neutral then stain. Careful though, it's easy to raise the grain, then sand through the veneer trying to repair.
Good luck.
Peter