You guys obviously don't get it. Coby and Helmeppo are like Garp and Sengoku.
Therefore Coby will never realize his dream of becoming admiral, being stuck at VA. and Helmeppo will become the Fleet Admiral
In my opinion the parallels exist but they aren't as clear cut as people think. If Coby resembles anyone I'd say that person is Kuzan rather than Garp. Just as Kuzan idolised Garp so too does Coby idolise Luffy. If you listen to the way they talk about their idols you'll hear the same fanboyish tone. Helmellpo doesn't have as strict a parallel but I'd say he lacks ambition and seems content to follow Coby which sounds somewhat like Bogart. When I say he lacks ambition I don't mean he has none, I mean his ambition to show up his father isn't great enough to elevate him to a position equal to or greater than Coby's.
Sengoku IMO has got no parallel among the rising stars because none of them seem particularly strategy oriented with the possible exception of Hina but even that's a stretch and is more appropriate for Tsuru.
Garp never wanted to be an Admiral whereas Coby does so him ending up like Garp wouldn't make sense since if he were offered the job he'd snap it up. Smoker more properly fills that aspect of Garp since he only wants to rise as high as necessary to facilitate his pursuit of Luffy meaning he doesn't have his eye set on Admiral and would refuse it if it limited his ability to chase Luffy.