With beneficiaries designated on the IRAs, these IRAs have nothing to do with Form 1041 or any need to obtain an EIN. Inherited IRAs would be established for the benefit of the children, not for the benefit of the estate. If the investment firm representative said that an EIN is needed for anything to do with these IRAs, I would consider as suspect anything that that rep told you.
Distributions would be the children's distributions. If the children are minors, they are Eligible Designated Beneficiaries and would be able to take RMDs based on life expectancy but would have to fully distribute the IRA by the end of the year they reach age 31.
