Aside from perhaps Kimmel, none of those shows would have on Samoa Joe no matter what marketing firm TNA hired. The other named programs draw from a higher level of celebrity that only a select few WWE wrestlers, never mind TNA ones, could hope to reach.
Letterman doesn't have wrestlers on. Hogan is the only one who does Leno. Conan would be a choice, but with the NBC/WWE deal a TNA guy being on might not happen.