Is it customary to use separate splines and/or separate spline types to interpolate different fields (e.g. translation, rotation, and scale)? Can this create any sort of artifacts due to misalignment?
@Kuragama Yes, the baseline thing is to have a different spline for each attribute. The misalignment you point out is typically a good thing, because it means the animator can place the minimal number of events in each spline, at just the right moments, rather than being forced to specify every attribute in the rig at every keyframe. However, there are natural ways to bundle events together; a typical interface is that the animator "scrubs" through the timeline, and any attribute that gets modified at that moment in time is inserted into the spline. Since edits are usually made at a very high level (e.g., manipulating a whole character, or running IK), these attributes do not all have to be set individually.