if you can split them (there is a named pally to avoid, he will make mince meat of you even if you are 65th, forget his name, but look him up) then pull to the furthest corner you can get to before you zone back out to GF.
once there. sick pet on him, and hope Darkness sticks. then put some of your faster dots, and nuke away. also keep ST up as they are all sub 55th and you can mez them thus stop them from casting heals. the next tic the mez will break due to a dot, then just spam your /pet kill button.
they are fun to hunt, but much better to hit Katta and hunt there then Felwithe just due to the issues with splitting them.
also Veksar is far better zone to play around in once you hit 59th, 60th is a cake walk compaired to 59th and the xp flys way better at that point too off of the same mobs.
the 1 and only time i tried to fear kite the felwithe guards fear never lasted more then 5-10sec. it became more of a mana sink, then it was worth it to have my rogue pet BS the pally.
ST is your friend as are your nukes. visit a friendly 65th mage and get pet toys, and DoT, DD, mana save, spell haste items before you hit them. that will help as well.