Fun in Prussia

One of a bunch of fun treasures I found this week. These four pieces came taped together, and shockingly were within my five dollar rule.
When I came home I found the little oval plate doesn't match the S&P and tray. It is Nippon. (bonus plate!)
The other three pieces have N Finn on them. Definitely hand painted. But the mark on the bottom looks weird to me. They are very pretty but I don't know too much about them. How many other pieces should be in the set? What about that odd Prussia mark? Thoughts?