Adventures with 'other' instruments...
I am somewhat familiar with the Kantele as well as the Kalevala having graduated from Suomi (Finland) college. I, too, would like to see a photos of the whole instrument front and back. Some things to consider are whether the tuners work smoothly. After 20 years some may be stuck in place or no longer hold when tuned to pitch. These are easily resolved problems. Make sure all the joints are secure. If not, you will need to glue them. Do you know who made your Kantele? If it has a finish on it, you can test to see what type of finish it is. If it is lacquer you should be able to put a new coat or two over it. It could be shellac. Or it could be some type of varnish. You may need to sand it down to bare wood, but I would avoid that if I could as I don't like sanding. If you like to sand, go for it. It looked like some of the dents could be raised using moisture and a hot iron. Looking back at your photos, I do not understand what is happening in the first photo with the string anchors. What are the strings going over in the photo? Also, if you want to you can replace the tuning pins with shiny new ones.
Just a few thoughts. I hope some of them are helpful.
"The dulcimer sings a sweet song."