I have completed the quest a number of times, and have found these froggies in two main areas.. 1) The bandit camp at 2400, 0 and 2) Undead camp at neg2500, 500. And yes, a couple of times I've seen them on tracking in Firiona Vie, but I fear the drachnids and didn't go hunting :)
I *once* found a ton warrior in the halway leading to the Temple, near the Trakanon zone. I have found a few in the area between Frogtown and the Trakanon zone, and I have found a few in the southeast corner of the zone, standing by the water.
I think pretty much anything around the two camps can be a placeholder. Devourers, scourgewings, gaz knights, vis shamen, kill 'em all. Don't bother going to Frogtown, it's too dangerous.. and you don't need to fight either the undead or bandit camps, just the stuff around them.
I estimate the drop rate for the totem to be 1 in 10. It's a big pain to get. Best of luck. Bring a ranger along with you to track :)