I would be very careful to leave a permanent job for a 6 month contract with only an "option" for extension. History has shown how "options" might work out. Ask the pilots in Helsinki how their option for a permanent contract looks like these days. Apparently the conditions for new joiners (FOs) have been reduced as well. The allowance and the basic salary were cut. Of course you will only find out during the interview...By now Scandinavian new-joiners should have understood that their dream about being based up north (except HEL on amazing conditions) is over.
Many FOs are leaving the ship already to SAS, EK, EY and others...