We now have confirmation that a new edition of Coenen's Symphony No.1 is being prepared:
https://www.youtube.com/watch?v=wv2UJn46OhY&lc=Ugzb8jTPBYbGitG-Wjx4AaABAg.9h-kCPkTkoN9jQu6dHT1G9 (scroll down)
I am informed that Symphony No.1 is in F major:
https://www.youtube.com/watch?v=pBhvXtfp6_A