Received rumblings that the project is "on hold". When asked for further comment, all I was told was "it's on hold."

Absolutely false. Switching to AECOM/Heery has delayed it a bit, because they are starting from scratch with the design — they were not even shown the Populous renderings so that they can be creative without being limited to what was done before. Architects were in town yesterday meeting with AD staff. Sales are very strong from what I've heard. Whoever told you that 
I asked if the switch could be the case as well, and he said, "It could. It could be a number of things."
I didn't push too hard because I don't want him to get in trouble, but I just wanted someone with more upstream info to post some details if they had them.
Thanks as always, CC.