"or is the court trying to decide who is the trustee and who is the executor?"

Isn't this jumping too many steps ahead, though?

"Her father has several trust accounts he was receiving income from."

Then you start with that trust document or that trustee. It doesn't roll into his estate, if there is a trust for it. The trust controls what happens in the case of his death as a beneficiary (or grantor? or?). Whose trust is it?

"One of these accounts split his brokerage statements pre death and post death."

Did you mean, the brokerage account which is not in a trust has beneficiaries who inherit the account? Or, it has no beneficiaries and that's why it rolls into the Estate? Or, does he have a trust that was the sole beneficiary on the account?

Because there is a sequence to these ownership rights.

"Pre death statement was labeled with his social security number and I'm filing his last return."

You don't use Statements. Do you have 2022 tax documents for any of this? For example, that first account by reference to a trust, is there a trustee that provided documents (or should have) when notified of his death?

The will might be disputed, but a lot of what you laid out would not fall under a will if any of these other provisions are in place. They would take precedence.