Currently it requires a lot of taps to choose between drag & drop, drag & drop copy, and multi-select.

When you long-press a calendar event the top bar changes and has a delete button, so why not add buttons to duplicate the entry or to switch to multi-select mode?

It seems like it would be more intuitive from the user end because most users will automatically long-press the item first and then they will look to see what options are available.