You can create a new Expressions category (by duplicating the original Dynamics category), changing the category settings, and then copying and pasting duplicates of the normal expressions into the new category and setting them to adopt the new category's positioning.

Also, if it's something you do often, you should take time to set everything up the way you want and save it as a Template ... Although, I do understand what you are saying and agree this could/should be much easier.

6 years ago?  and no mods/upgrades?  Seriously?  What I would like to see (i.e., how it would be if this were my program), an option (in the standard expression tool) to place, by default, expressions for each staff above/below the staff.  E.g., for a dynamic, place the "mp" above the treble staff, place it below for the bass staff.  It's an option: for some scores, all above (or below) is fine; for others, not so much.  Same true for tempo alterations, btw.  And if I do it regularly, then sure, save an "opposing baselines" personal library to load - but all that has is a different default from the OEM library, not an entire duplication of the whole expression library.

My $.02 worth..

Jeff Kantner

There is a "Dynamics above staff" script in Finale Lua Scripts which is quite convenient attached to a keyboard shortcut