Went through the few threads of this and have the following.  This is subject to change when they lower the levels of the mobs we need to fight to learn the skills (aka not fighting lvl 25s to learn a lvl 16 skill etc)  Feel free to chime in and add/update the list

Read in the wind 1 - lvl 26
Spiders outside Trengal keep
Infineum Simularum , southern infineum mine fields

Read in the wind 2 - lvl 36
Roaches in Darguns tomb
humanoid´s in the cave of Karrus Hakrel
River palace

Read in the wind 3 - lvl 46
Handlers in Raz (easiest option imho, they use the skill at roughly 50% hp)
Flame AND Flare maidens in raz

I got my skill updates from Flare Maidens couple days ago. Not sure if it was pure luck but at least it seemed to me that it was a lot easier to get 'em from the Flare ones than Flame Maidens. I only got one update from about 10 Flames and it seemed to me that they were always casting something else during the 50% spot where they usually tend to "teach" skills. Took agro on two Flares after that and got the updates.

With the update in levels you can learn RITW I figured I could learn RITW2 at 34 in Dargun's tomb... However, after much duoing with a friendly Disciple, I still have no learned it. I've looked for the bats but we had to turn back before we could get that far.

When you say "roaches" I assume you mean "Infesting XXX's"?