Wil Ceron wrote:
I hope you know Clark Ashton Smith (and Robert Ervin Howard) as well.

If not please make your acquaintance especially with Smith, and I can assure you, you will not regret it.

Lovecraft, Howard and Smith were "The Big Three" from "Weird Tales" in the nineteen twenties and thirties.

I'm sure that Jack Vance has read stories of all three of them.
Perhaps even influenced by one or all them?

Of course! I have read all of C. A. Smith! Perhaps the greatest of them all. And I do occasionally read R. E. Howard as well,  even though I find him too heavy on the action. But at his best, he is up there with the genius of the others.

Yes, I believe Jack Vance did. He has at least commented on enjoying Smith.