My name is Heidi Koskela Amell. My grandfather Albin Koskela was Lempi's younger brother. If you or any of your relatives have an interest in the Koskela side of things, I've got a family tree that goes back to the 1600s and I'd be glad to share the info.
I have recently been in contact via email with Nicky Chamberlain and will be sending Koskela info to her as well.
Good luck in your search with your father's family.