What is "it" that tells you the children do not need to file? That is not correct if your children are your dependents. For 2018, a dependent with unearned income over $1,050 is required to file a tax return. Since the 2018 Alaska PFD is $1,600, every dependent child who receives a 2018 PFD is required to file.
(You might have the option of reporting the children's PFDs on your own tax return. Doing so would satisfy their filing requirement.)
