Melinda listened, mulling this over carefully and applying it to what she knew about throwing off an Imperius. Clearing her mind of emotion would be difficult, but she thought she could muster the anger to resist, to stubbornly hold her ground. Especially with Ella. She had plenty of fuel there.
"What about someone planting thoughts?" she asked. This was really the relevant part. She didn't so much care about resisting all Legilimens, she just needed to make sure Ella couldn't get in and convince her to stop what she was doing when she was right there. If she could learn to lock out thoughts not her own, she'd consider it a success, not caring about reading memories. There were few she was all that worried about hiding. The most effective thing to use against her that would be found in her mind -- Marek -- was plainly obvious to anyone with eyes.