Dont rely on getting Northfin food... they are pretty quick, but it is getting close to the holiday.
If you were closer, we have bunches of samples we could share, also if there is a killifish group near, they frequently will have a good assortment of live food to hand
But good luck! I am sure they are just a little upside down from the new digs, dont stress too much!
But test as much as you can, just in case, trying so much food that doesnt get eaten can fowl your water.