PLEASE I MEAN PLEASE DO NOT MESS UP THE CONCEPT OF Harley Quinn if she is going to use weapon mastery please make sure she uses Dual Pistol and Two Handed in her attacks ..... Thank you that is all
If you're talking about legends, legends characters won't be affected by WM as mentioned several times by devs.
As of if she is altered by the solo duo or by if any more batman upcoming alerts or launchs in the future.