I hope you are not trying to mess with our minds here Is there another Phu Ruea that does not lie in Loei Province in Northern Thailand?
When I saw the first neps you asked about I was sure you had found them in southern Thailand near the Malaysian side. N. gracilis and N. ampullaria has been found there, I don't think I have read that they can be found much north. When I saw the new pics with N. macfarlanei (first photo) and the N. rafflesiana (picture 2 and 6) I was even more sure. As far as I know none have been found in Thailand, N. macfarlanei is endemic to the Malaysian Peninsula, and N. rafflesiana is common in some part there too.
On second thought, they might have been introduced there by people.