1) In western Finland farmers did not have family names until late 1800's or mandated by law in 1920's. They used farm names as identifiers, but they are not family names. (I trust you have read some introductions to Finnish research?)
2) I don't know Malax, so I can't explain except that in most of the places I research that is also the case. a)Instead of Google maps try http://kansalaisen.karttapaikka.fi/kartanhaku/paikannimihaku...
b) remember that same name is not necessarily where the farm used to be. In the results of my previous reply you will find on the first page a map (in pieces) from 1800's
3) Unfortunately relying only on Hiski is guesswork, not genealogy. http://www.sukuhistoria.fi/sshy/index_eng.htm
has digitized parish records but Vaasa area is currently not very well covered. Try to get hold of the rippikirja/husförhör records as you risk wasting your time researching wrong people. At the least for 1800's check against henkikirja (tax census) which is available also among yesterday's results.
As you can see there are only a couple of people giving replies here so you might also want to try out Finlander Forum where there are many people interested in Swedish speaking coastal areas http://finlander.genealogia.fi/