Kill other things in those zones. Other mobs are placeholders for the HG/eyes. The example I remember is that bixies in EC were placeholders for griffons. If you know the paths the HGs/eyes take, you can kill things that look like they're walking the same path. Otherwise, kill as much as you can in that area.
In East Karana the HG pop on Crag Hill where Tarbul used to spawn for i think Druid Epic. I have killed everything that moves on that hill and still no HG.
So does today's patch mean they are also putting back the missing merchants? it wasn't in the patch notes, and a couple of them were the only vendors to sell certain items.
At least adding the cultural items would be great, but I'm assuming if they did that they would have said it.
As a tracking class, the best way to churn through unknown PHs is to use tracksort normal, and keep killing the things lowest on the list that MIGHT be PHs. Tracksort normal is based on time since spawn, so the things on top are the newest, and the things towards the bottom are the oldest. In zones like the Karanas, there are plenty of npcs and vendors that can act as time markers in the tracking list. While clearing as much other random trash as possible, hunt down any of the trash that's below the NPCs on track. Once you've cleaned up the oldest spawns, keep doing that general thing of tracking to the oldest trash while killing everything else on your way there.