Oh. I'm a native nordic person but somehow I've never heard of "Mikka", there's Mika, Miikka, Mikko, etc though. Is Mikka male or female? I assumed it would be male. I actually tried to google it but found little more than a discussion where someone was trying to come up with a unique name for their baby... Nothing wrong with using that name in your story though.
p.s: As a last resort I actually checked the official registers - finnish, as the Mikka in the story is finnish, right? - and according to them since year 1899 there have been fewer than 36 Mikka's, fewer than 21 of them male and fewer than 15 female (for some reason it actually says "fewer than" with each number). First use was in the sixties, presently there are (again, fewer than for each) 10 living Mikka's, 5 of them male and 5 female.
p.p.s: just noticed your correct use of "ä" in Häkkinen, kudos =D
