Some more information. I have tried applying a Filter in web.xml and this is the trace from the point when I click search until the search page rerenders.
... in the log is duplicates. The logging is from inside the filter and from the getPerson() method inside of the PersonList class.

Unfortunately I can't get the åäö to work in the forum either so one has to pretend that the aao in the log-trace is the Swedish characters and the others are the mangled ones...

12:12:29,671 INFO [STDOUT] Calling UTF8Filter:
12:12:29,671 INFO [STDOUT] Request CharacterEncoding: UTF-8
12:12:29,671 INFO [STDOUT] Response CharacterEncoding: UTF-8
12:12:29,671 INFO [STDOUT] Parameters: {personSearch:search=Search, personSearch:j_id24:lastName=, personSearch=personSearch, javax.faces.ViewState=_id2, personSearch:j_id19:firstName=aao}
12:12:29,692 INFO [STDOUT] personList.person.firstName: null
...
12:12:29,702 INFO [STDOUT] personList.person.firstName: åäö
...
12:12:29,709 INFO [STDOUT] Hibernate:
 select
 person0_.contactFK as contactID0_,
 person0_1_.version as version0_,
 person0_.firstName as firstName2_,
 person0_.lastName as lastName2_
 from
 Person person0_
 inner join
 Contact person0_1_
 on person0_.contactFK=person0_1_.contactID
 where
 lower(person0_.firstName) like concat(lower(?), '%') limit ?
12:12:29,714 INFO [STDOUT] personList.person.firstName: åäö
...
12:12:29,752 INFO [STDOUT] personList.person.firstName: aao
...
12:12:29,757 INFO [STDOUT] Hibernate:
 select
 person0_.contactFK as contactID0_,
 person0_1_.version as version0_,
 person0_.firstName as firstName2_,
 person0_.lastName as lastName2_
 from
 Person person0_
 inner join
 Contact person0_1_
 on person0_.contactFK=person0_1_.contactID
 where
 lower(person0_.firstName) like concat(lower(?), '%') limit ?
12:12:29,761 INFO [STDOUT] personList.person.firstName: aao
...
12:12:29,792 INFO [STDOUT] Calling UTF8Filter:
12:12:29,793 INFO [STDOUT] Request CharacterEncoding: UTF-8
12:12:29,793 INFO [STDOUT] Response CharacterEncoding: UTF-8
12:12:29,793 INFO [STDOUT] Parameters: {cid=3, firstName=åäö, lastName=}
12:12:29,808 INFO [STDOUT] personList.person.firstName: null
...
12:12:29,827 INFO [STDOUT] personList.person.firstName: åäö
...
12:12:29,946 INFO [STDOUT] Hibernate:
 select
 person0_.contactFK as contactID0_,
 person0_1_.version as version0_,
 person0_.firstName as firstName2_,
 person0_.lastName as lastName2_
 from
 Person person0_
 inner join
 Contact person0_1_
 on person0_.contactFK=person0_1_.contactID
 where
 lower(person0_.firstName) like concat(lower(?), '%') limit ?
12:12:29,949 INFO [STDOUT] personList.person.firstName: åäö
...
12:12:30,358 INFO [STDOUT] Calling UTF8Filter:
12:12:30,358 INFO [STDOUT] Request CharacterEncoding: UTF-8
12:12:30,358 INFO [STDOUT] Response CharacterEncoding: UTF-8
12:12:30,358 INFO [STDOUT] Parameters: {}

Found it! Oldie but goldie...

<Connector port="8080" address="${jboss.bind.address}"
 maxThreads="250" maxHttpHeaderSize="8192" useBodyEncodingForURI="true" URIEncoding="UTF-8"/>