Tell me whether criminal proecutors are either appointed (by whom) or
elected (by whom) in Australia, Canada, Germany, Sweden, and
Switzerland

In Australia procecutors are employed by the Office of the DPP
(Director of Public Procecutions) in each state. This is an Office set
up by legislation and is a seperate body from State governments.

some sites of the DPP in each state:

Western Australia: http://www.dpp.wa.gov.au/content/faq.htm
 
Australian Capital Territory: http://www.dpp.act.gov.au/

New South Wales: http://www.odpp.nsw.gov.au/

IN Germany, prosecuters are NOT elected.  "Staatsanwalt" is a civil
servant position either at the state ("Bundesland") or federal level.

Incidentally, they are obligated to consider all evidence in a case,
also that in favor of a defendant, so they are not like your TV/film
district attorney (Santa Maria, Cal. ?), going tooth and nail for a
prosecution.