I have MM 14 PE, so hopefully, this information applies to MM 15.  Using Beatbox as an example, here is what I found:

After creating the Beatbox "object," simply highlight it in the track, then right-click. In the menu, hover over the "Rack effects" option, and from the next menu choose "Time Stretch/Resample". The BPM is right there for the Object, rather than for the whole project.

As far as the Remix Agent, here is what I found in the online Help:

"If songs longer than 15 seconds are dragged into the arrangement, the Remix Agent is started automatically. When loading short samples (< 15 sec) the tempo is specified automatically and some loops are similarly automatically customized to the tempo of the arrangement. This also applies to previewing in the Media Pool (Smart Preview).

This method can be deactivated individually in the audio/video options (A key). You can find out more in the "File" menu > "Properties" > "Program settings" section."

Elsewhere, the online Help indicates that the "songs longer than 15 seconds" refers to something like a song from a CD or MP3, to which you want to add additional tracks from within MM.


Hope that helps.