They are pr. something like this:
Bedrich - BED-zhisch (with r as in Dvorak)
Frederico - fre-de-REE-koh
Frederik - FRAY-de-rick
Frederikke - fray-de-RIK-kuh
Fredrik - is this really Finnish?
Fredrik - FRAY-drick
Friðrik - FREETH-rick (with th as in "the")
Friðrika - frith-REE-kuh
Friederike - frid-REE-kuh
Frigyes - FRID-yesh
Fryderyk - FREE-de-ryck
Best wishes, Fredrika ;)