CONCERN: I'm still concerned about "change addresses" that might be generated during these "sends" from the temp non-HD wallet.
That temp wallet is still an HD wallet, there is not way to make a wallet that is not HD in armory. You have just imported all of your keys into it, and all of the addresses that were generated from the HD are still there. So any change will be sent to an address that is part of the HD keys in that wallet.