As Steve says, one can have any number of Instances of music (or any Asset), in a Timeline. Once it has been Imported, it can be used an infinite number of times. Also, each Instance can be Trimmed, so a Video Clip could appear with different In & Out Points (same for an Audio file), on the same Timeline. What one sees (or hears) on the Timeline is but a reference to a certain part of the actual Clip, which is still sitting, untouched, on the computer's HDD. The actual media is not used, but a reference to it, is created, in XML language, for use when one does an Export/Share. What is seen/heard on the Timeline is but a representation. I find using multiple Instances of an Asset, to be the easiest workflow.
Now, if one has added Effects to an Instance, and wish to add those Effects to another Instance, one would just Select that Clip w/ Effects, Rt-click on it, choose Copy, then Select and Rt-click on the other Instance, choosing Paste Attributes - all Effects, and their setting will be added to the second Instance. Note: if one wishes to have different adjustments to the settings of any of those Effects, they would just make those, and those setting changes will NOT affect the original Clip, from where the Effects were Copied.