Assuming source transactions with amortization schedules (JE's, VB's) are in closed periods, but we want to close/stop those amortization schedules, are there any options, beyond re-opening? Ideally we'd like to wipe out all amortization schedules to begin anew.

I don't think it's possible to create a 'new' one schedule if the source transactions are in closed periods. Why do you need to create a new one though? You can edit the amortization schedules that do not have JEs yet if the preference to do so is turned on.

One reason is that there are custom segments we'd like to include on amortization that were not on the source transaction. But we can't edit the source transactions because it's a GL impacting change. So we currently have to manually edit amortization JE's.