Brubeck's placement is based on both his solo work and his group work.
I think what I'm about to say in this paragraph is a fair representation of jazz history as it is usually written, in fact always in the writings I'm familiar with. European jazz as a whole isn't a very big part of jazz history; America dominates jazz. This was especially true prior to the late '60s, at which time the contributions of Europeans increased. And the most important European jazz artists from the late '60s to the present don't play gypsy swing. So I think this adds of to a fairly small place in jazz history for gypsy swing.
Most of the other influence you cite I haven't seen anywhere else. Christian southwestern blues based jazz is quite different from Reinhardt's gypsy folk jazz, though I wouldn't be surprised if he was a minor influence. I was say his most important influences are that he was the first major jazz figure in Europe, the first major jazz guitarist, and a major influence on many jazz guitarists of the '30s. I don't doubt that his influence was felt into the '70s, but that can be said of many others, including Christian. Tributes are indicative of the esteem of the artist's work by other musicians, so they're relevant to his placement, but they're not influence.
Django and Brubeck came up in reference to Hancock's placement on the list, so here are 2 questions for anyone who wants to answer them. (It's also OK to just answer one of them.
) Is it wrong to have an artist who emerged in the last 50 years in the top 30 of this list? Should Hancock be the highest ranking artist who emerged during the last 50 years? Clarifying the criteria, it's 1/2 influence, 1/3 the quantity of highly esteemed recorded work, and 1/6 reputation as a musician and/or composer.