You may need to remove the mulch and soil surrounding the stinkhorn, yes. Even if you've removed individual mushrooms, their spores can still survive and grow in the surrounding mulch and soil.
Try subtly asking her/him why she's/he's acting this way. Sometimes people act out if they're having a bad day or if someone let them down. If those aren't the reasons...
Promise that you will study hard and retake the test. Perhaps you could (calmly and respectfully) try to compromise. Maybe they could let you use the phone for an hour...
You can ask her to stop, and make it clear to her that is makes you and your boyfriend uncomfortable. If she doesn't stop, then tell the manager or another...
It might be worth trying a fungicide, if you don't want to disturb your mulch. On the other hand, the fungicide will probably be more effective if applied directly to...
As you're putting on the harness/taking it off feed her treats to distract her and teach a new habit of not biting the harness as it is put on/taken off....