What alignment specs were used? Was any driveline work done at the same time?
The vibration is unlikely to be the suspension components, much more likely that it’s a wheel, tire, bearing, or driveline issue.
The creaking could definitely be a bushing. If the suspension was tightened while hanging instead of at ride you may have torn a lower control arm bushing. If the bushing is already torn then loosening and re-tightening at ride height won’t change anything. And if the creaking is a bushing, it’s most likely already torn. But even in that case, the bushing is unlikely to cause a steady speed vibration. The steering or handling might feel wonky, the creaking would make sense, etc. But a vibration at a constant highway speed is unlikely.
