I wouldn't overly worry assuming it everything is tight and safe, it will manifest in time with your equivalent of an MOT. I would ask someone to check to it over with a ramp and attend to when it become more evident what it is.
My car squeaks at speed bumps assume something somewhere in the suspension is softer than the last car.
Noticed you're in a cold climate and could be worth going round all the bushes and joints with silicone spray.
Could be, but probably worth just riding it out and it will become more obvious over time what the fault is. Callipers are expensive and you should only need to replace if and when the capiler seals go.
I had a strange vibration front the front from getting my Ceed at tickover than went through the car, a lot of searching lead to a vibrating undertray that has now been wedged with foam to stop it making a noise.