I'm not suggesting that the qhal were frogs!
Yes, they seem to be more like elves/eldar physically. And yes, the prologue to Gate of Ivrel says that "The technology had been discovered in the ruins of a dead world".
But the parallel and source of inspiration, surely, is between the qhal as arrogant travellers in time and space interfering in the development of other species on other worlds, and the Slann as ... arrogant travellers in time and space interfering in the development of other species on other worlds!
I'd be really surprised if Cherryh wasn't the direct source of inspiration for Halliwell et al.