-> Motion Seq -> Lane -> Load Sequence
Is it possible to have a graphical preview and an audition of the sequences (Big Bell 1; Big Bell 2 etc.) before selecting them?

Similar to selecting a curve type using the "data dial" (Mod / Control -> Control Assign -> curve type), Here I can preview and audit them without selecting them first.

It is not clear to me the distinction you are making in how these are selected. You are not so much previewing and auditioning them when you select CURVE TYPE, you are actually applying them. The Motion Sequence LOAD function is exactly the same. You are not so much previewing them you are applying them... That how you audition them - you apply them.

Work with it a bit more, the MOTION SEQUENCE names are highly descriptive (more so than the Curves Types). The thing with the hearing the Motion Sequence is you must apply it to a parameter for the control movement to manifest itself.

It is easiest to understand the shapes by applying it to a Destination that has obvious response. PITCH for example, you want to hear the difference between BIG BELL 1 and BIG BELL 2, apply the LANE to a PART PARAMETER PITCH - a Ratio of 0 will produce no change, any value other than Ratio 0 will cause the pitch to animate.