Am I totally misreading/misinterpreting this, or does it confirm my hopes that this account can still be moved to a discount broker as a beneficiary IRA?

You're reading the wrong section. According to your first post this account is already in a beneficiary account for you. The section of Pub 590 that you most recently quoted pertains to transfers from employer plans to IRAs. It appears that has already happened.

What you want is a rollover/transfer from one beneficiary IRA to another. Yes, this is possible, even with annutities. There's a separate discussion in Chapter 1 of Publication 590 regarding rollovers from one IRA to another.

Phil