I have not tried to check library databases. In the 90s I asked about Star Trek books from the library and they told to me about some finnish titles but back then I did not like to read in finnish so I loaned Star Trek books in english. The finnish translations would be more of a curiosity than anything else, so I'm not actively searching for them but alvays when I go to a used bookstore I do ask if they have any. Checking the library databases is a good idea thank you.
There are really no finnish fan-pages for Star Trek and I dont know if there is a finnish version of memory alpha as I use the english one. Also Amazon is not used all that much in finland so anything finnish can be a bit hard to come by from there, I did check Amazon but there was nothing there.
Finland is a fairly small country and it seems that these days intrest in Star Trek has become fairly marginal. So any online resources are kinda hard to come by in finnish, and I probably would not use them all that much if there were.