Did Lamia's death had anything to with Ethan? I'm pretty sure it has something to with Ethan because why would Aquila be so triggered when she mentioned his name, omh.
Aquila definitely traveled back through time. The reason why his personality changed by 180 degrees is probably because he's not his past self anymore. According to the time Uri got his hand injured, then Aquila probably arrived to the past some time after that or just right before the time Duke...