Obviously famous company has a big significance on general perception, but I feel both Hampton and Elmo are considered more than just Bud imitators. Red just may just have been in the right place at the right time, although his block chording
did have imitators.
For overlooked pianists who could really play, I would nominate Ronnie Ball from the Tristano school. Another would be Oscar Dennard, who played with Lional Hampton in the 50's, before dying young...
Q