Thought I'd throw in an update:

I was able to pick a different final destination (LAS) without a change fee. T space did not exist for my flight at the time of contacting them. They created the reservation but said they would reach out to AA to make the space available and email me with a link to pay the new taxes in a few days with my miles to be refunded the following day and the existing reservation's taxes refunded in 7 days. In that time, I saw my reservation updated but my new connection unticketed. Just paid for my ticket today and saw all error messages disappear afterwards. I am pleased with how easy the experience was.

On a side note, it looks like they were unable to request AE or QX flights.

Hopefully I'll be able to freshen up in the Flagship lounge prior to my connection.