Wolf Stance is huge for the trap rat - it solves the velocity and FHR problems simultaneously (you won't need any FHR sockets or orbs with WS).
Sadly, the fastest FHR breakpoint for rat is 5 frames, so you'll need high defense to avoid hits, but a 6 or 7 frame hit recovery = certain death.
Easiest way is to get it from two pieces of Community Set. I use the boots + gloves (avoid the crown, armor is meh), belt other good choice, but Ghal belt is great for this build. Psychic Scream proc from belt is great for crowd control.
If you have WS, you may want to respec to Faerie Fire from Force Of Nature. You'll lose about 2,400 elemental damage per hit (not a small amount), but gain % avoid, and it will make your on striking procs godly since you'll be running around like a rabid rat on crack and enemies will be running through your faerie trail.