Why ask? Just like you interact with everyone else. Finnish ain't exceptions.
Finnish or Finns
Finnish People's Unity Party was created in 1972.
Finnish People's Blue-Whites ended in 2010.
Finnish People's Blue-Whites was created in 1993.
'Better people' litteraly in Finnish is 'Paremmat ihmiset'.
People from Finland are of Finnish nationality.
Finnish People's Democratic League was created on 1944-10-29.
Yes they could.
The most common Finnish eye colours are blue and brown, so yes.
People from Finland are called Finns, or Finnish people.
In English it's Finnish or a Finn. In Finnish it's suomalainen.
Finland's main language is Finnish. The second official language is Swedish.