A question about Dragoons.

Can all Dragoons utilise jump skills etc or only the Azure dragoon?.

I'd say all of them would be trained in leaping, with a pretty high degree of certainty based on the Heavensward opening alone.

However, in the interest of due diligence, I do believe Estinien (though an Azure now) speaks of his training to master the Dragoon's jump, Heustienne leaps onto a dragon during the job storyline, and Gerolt says that the Gae Bolg, forged for every Dragoon of Ishgard, has the little wingers on it to aid in the arcing leap of the lancer onto their flying prey.

I think lore wise, only dragonfire dive was unique to the Azure Dragoon (at 50 cap); the other Drg abilities were just that, Drg abilities

Dragoons are specialized to bringing down dragons, and the reason for that is their jump attacks. So essentially you need to be able to jump to do your job.

Dragon Fire Dive acording to the story was created by Haldrith the 1st Azure himself and passed down from Azure to Azure. (The Crystal taught it to us) and besides us only Estinian has ever used it.
As for all the post 50 abilities, thoae seem ti be origenal skills of the WoL empowered by Midguardsormrs bond with us.