Is polygamy legal in Sweden

Answer 1

Polygamy is NOT legal in Sweden!

95% of Swedes used to below to the Church of Sweden which is Protestant/Lutheran. But these days is closer to 70%, mostly due to Immigration but also the separation between state and church that took place in 2000.

Answer 2

Yes. With a dispensation from the County Administrative Board..

As noted on the wedding license application form in a footnote.

"De som är halvsyskon får ingå äktenskap efter tillstånd av länstyrelsen. Detsamma gäller de som är helsyskon genom adoption."

or

"Half siblings may marry after approval by the County Administrative Board. The same applies to full siblings by adoption."