Kurapika can only be really effective against the Spiders. I guess the entire DC will made up of Spider members.
And are you honestly telling me Leorio is elite? We love him, but he's nowhere Gon's little left foot's finger's level. In experience, strength, fighting instinct or what have you.
How can you still imply that Gon is not strong enough, but Leorio is an elite? How does that work, considering what we know of each one of them?
Also, if we're just talking semantics (since Leorio and Kurapika are chosen by the elites –-> they're elites themselves), then we're straight up cheating, cause had Leorio said "call Gon", then Gon would've been the twelve zodiac. Had Leorio said "call Hanzo", Hanzo would be the twelve zodiac. Had Leorio said "call Gimli, son of Gloin", and you catch my drift.
I think it has more to do with Leorios image, which help the Hunters expedition to the Dark Continent… he almost becaem the new chairman, and was able to land a hit on Gin (yeah he let him but no one else knows that) which made him really popular among the other Hunters, especially those who hated Gin and wanted to see him get smacked... so in the end, it's not his fighting ability, but his image that will aid them in this journey, which is why Cheadle decided to invite him. Me thinks.