Expected size of startup package for a tenure-track position in Finland
There is very little any public information on this available anywhere.

I did some googling and here is a summary of what I was able to put together from some random documents written in Finnish (from Helsinki, Tampere, and Oulu): a reasonably normal startup package for a new tenure track or tenured position in Finnish universities appears to be enough funding to hire 1 doctoral student or postdoc for 1–3 years.