Null and Avoided

Very easy achievement to accomplish: Just use your aoe stun when the round starts, since the Seekers physically can't go across the map fast enough to tag you as soon as the round starts.

Hitting ability 4 at start of round still works for this. You can get a few in every round without issues.

In the prop hiding phase simply stand still, use your stun and allow the found status to drop.
Notes: may have to be done in the last few moments of the hiding phase or first few seconds of the seeking phase, I got 4/5 beforehand so I was unable to test further.